I have tried testing around with a friend who has more packs than me, and we've found out similar cases than Japanic2012: some situational, non-player chosen outfits somehow get "stuck" on Sims and exported with them on the Gallery despite being nowhere to be found in CAS–even without any mods or cheats. But it seems that we have multiple bugs with different symptoms.
For CAS, we noticed the following:
- Household Sims in certain careers that are exported to the Gallery are exported with their career outfit. Basically, if a Sim in a career from a pack X, they can get a career outfit with CAS parts specific to that pack. If exported to the gallery, that pack X will be flagged in the Gallery, even though the outfit cannot be seen or modified in CAS.
- We witnessed it for StrangerVille's Military career, Get to Work's Scientist career, Island Paradise' Fishing career, Seasons' Gardener career and City Living's Critic career.
- How to reproduce it:
- De-activate all DLCs but one of the above.
- Create a Sim with outfits using only base game CAS items.
- Enroll them in a career included in the only DLC you have active.
- Repeatedly promote them by any means until they reach a career level whose career outfit include DLC CAS items.
- Export the household to the Gallery.
- Look up which DLCs are flagged, and which CAS items from these DLCs are included with the "Show used items" button.
- Send the Sim to work or put them into their career outfit
- Compare what they now wear in Live Mode with the list of items including in the exported household according to the Gallery. (This doesn't work if all CAS items worn by the Sim as their career outfit are unlockable items that never show up in the in-game lists of Gallery items.)
- If household Sims have full-body career outfits which already includes shoes, random shoes are attached (though never seen since they are overwritten by the full-body outfit's own shoes). These shoes can be picked from any pack and will ignore clothing preference (masculine/feminine). It seems to be like Eco Lifestyle's Civil Designer career when Sims would get very random shoes that seemed inappropriate for the job (high heels, slippers…), ignored the Sim's clothing preference, and were picked from any and every DLC. Though patched for Eco Lifestyle, a household Sim with a career from another DLC careers can still have its DLC flagged. As long as their career outfit is a full-body outfit which hides any shoes chosen in CAS, random shoes are apparently attached to this career outfit.
- This includes full-body career outfits from StrangerVille's Military career, Get to Work's Scientist career, Island Paradise' Fishing career, Seasons' Gardener careers (and probably the Base Game's Astronaut career as well according to Japanic2012), where all outfits comes with shoes included.
- How to reproduce it:
- De-activate all DLCs but one of the above + as many DLCs you want which include new CAS shoes.
- Create a Sim with base game outfits only, take note of their clothing preference (masculine/feminine).
- Enroll them in one the above career.
- Repeatedly promote them by any means until they reach a career level whose career outfit is a full-body outfit with shoes attached (and which overrides your choice of CAS shoes if that outfit is used in CAS).
- Export the household to the Gallery.
- Look up which DLCs are flagged, and which CAS items from these DLCs are included with the "Show used items" button.
- In addition to the DLC matching the Sim's career, there is a chance that shoes from another DLC are being flagged in the Gallery, and/or that these shoes do not follow the Sim's clothing preference.
EDIT: Seems like it also affect bottom-only CAS items which include shoes, including StrangerVille's Military cargo pants which have boots attached to them.
Also, per Japanic2012's later post, one does not need to enroll into the base game's Astronaut career to get an Astronaut suit with random DLC hidden shoes. Simply board a fully-built rocket.
- CAS parts for some situational outfits somehow get "stuck" on Sims, which are then included when they are exported on the gallery. If the game creates a new Sim to fill a role, or picks an existing one, their situational outfit might somehow "remain" around. For instance, we noticed some pre-mades (Bella Goth, Dina Caliente…) suddenly becoming Spellcasters in the Magic Realm with Realm of Magic, or strolling in Vampires' Forgotten Hollow with outfits from these packs. After exporting them in the Gallery, CAS parts which they wore in the Magic Realm or Forgotten Hollow were flagged in the Gallery
- How to reproduce it: Difficult to do, but this could help:
- De-active all DLCs but one of the following: Realm of Magic; Vampires; Spa Day; Discover University; Bowling Night.
- Trigger a situation where pre-mades Sims can have situation outfits from these packs, or where the game creates new Sims, like one of the following:
- Go to the Magic HQ for the 1st time in a new save;
- Wait until pre-mades Sims or homeless Sims walk by in Vampire outfits in Forgotten Hollow;
- Visit a Spa lot;
- Visit UBrite or Foxbury lots when university organization events are happening in the neighbor;
- Attend a graduation ceremony from UBrite of Foxbury;
- Join a Secret Society as a university student;
- Visit a lot with enough bowling lanes to attract Sims in bowling outfits
- Take note of which Sims wore situational outfits in these situations
- Take pictures of these Sims as they appear with these outfits in Live Mode (including face close-ups for piercings, make-up and necklaces)
- Modify their household in CAS to remove all DLC items from their outfits, and delete all Sims you didn't witness in situational outfits
- Export the household
- Inspect which DLC items are included in the household according to the Gallery, and compare them with your pictures
- Note: you can also try this with a Sim that appear as Fisherman in Willow Creek; they will wear the base game's full-body fishing outfit… and potentially be flagged in the Gallery with random, hidden shoes from any pack.
- CAS items packed into the base game in July 2019 can still flag their old DLCs in the Gallery depending on which swatch is used. I recall that Simmers who own packs to which these items were originally exclusive were given access to new swatches (perhaps to compensate for these items now being in the base game). These swatches are not shown in the CAS interface as belonging to any pack (there is no pack icon in their thumbnail), but the Gallery will flag them anyway. I believe this one is more an issue of pack-exclusive swatches being incorrectly shown in CAS as "base game" items (rather than the Gallery incorrectly flagging packs).
- If any of such CAS items was used on Get to Work's mannequins placed on lots or rooms exported to the Gallery, we saw the same behavior, just like households exported to the Gallery.
- Hairstyles and make-up are sometimes not synced for career/situational outfits when changed in CAS for "normal" outfits. If we have a Sim who is originally using a hairstyle or make-up from a DLC and whose hairstyle and make-up is synced/copied to a career or situational outfit, replacing theses hairstyles and make-up by base game items in CAS changes nothing to career or situational outfits. Eventually, these get exported in the Gallery, flagging their respective pack, even though they aren't seen or used in player-modifiable CAS outfits.
- How to reproduce it for career outfits:
- Create a household with a single test Sim using exclusively base game items, and a single Everyday outfit
- Change their Everyday's hairstyle or make-up to use a single DLC hairstyle or make-up.
- Install this test Sim in a lot and go in Live Mode
- Acquire a career outfit by any means (get a new job which has a work uniform, get promoted…)
- Go back in CAS by any mean, and replace your test Sim's Everyday hairstyle/make-up to remove any DLC item
- Go back to Live Mode, and send your Sim to work
- Inspect what hairstyle/make-up they have. If they still have their previous DLC hairstyle and/or make-up, proceed to the next step
- Export this Sim's household to the Gallery
- Inspect what pack has been included, and what item from this pack was used. They should have their previous DLC hairstyle and/or make-up being included, despite it having being removed from their Everyday outfit. (Is perhaps the DLC item stuck with the Sim's career outfit?)
- How to reproduce it for situational outfits
- Same steps as above, but acquire a situational outfit (like putting a Spa towel on) on step 4 instead of acquiring a career outfit
- Unlockable CAS items or craftable Build items don't consistently flag their packs in the Gallery. Depending on the pack, items that are unlocked in Live Mode (and that will usually not show up in the in-game lists of items included in a pack) may or may not flag households with the pack they [the items] come from.
- For instance, some items that do not appear in CAS until they are unlocked–such star-shaped earrings unlocked through Eco Lifestyle's Civil Designer–do not flag their pack of origin in the Gallery if you use them on a household Sim.
- On the contrary, other items that do not appear in CAS until they are unlocked–such as Get Together's Daft Punk-inspired DJ mask–do flag the household with the pack, but do not appear in the list of used items from this pack, and neither in the in-game list of items included in that pack. It seems to depend on which pack they are from.
- Unlockable items from Nifty Knitting Stuff, Journey to Batuu and Paranormal Stuff which show up in CAS before being unlocked always correctly flag their pack when in a build exported to the Gallery and show up in the list of used items.
- If any of such CAS items are used on Get to Work's mannequins placed on lots or rooms exported to the Gallery, we saw the same behavior, just like households exported to the Gallery.
- When used uniforms for Retail, Restaurant and Veterinary lots, such unlockable CAS items never flag their lot when it is exported to the Gallery.
- Pack-exclusive food, drink and plants "crafted" in Live Mode and left on lots or rooms exported to the Gallery flag their pack of origin, but do not appear in the list of used items.
For Build mode, we've seen the following:
- Some Build items don't show up in the in-game list of items included in a pack. When such items are used in a build exported to the Gallery, their pack of origin is flagged, but the items aren't in the list of used items from said pack. This affects the following Build item types:
- Roof patterns
- Roof trims
- Friezes
- Exterior trims
- Foundations
- Platform trims
- Fences
- Stairs and ladders
- Stair railings
- Columns
- Spandrels
- Terrain paints (using the Paint Tool in Build Mode)
- Pool trims
- Pool Water Styles
- Fountain trims
- How to reproduce it:
- On the main menu, select "Packs"
- Select a pack which includes items of the type above
- Scroll through the list of this pack's Build mode items to inspect if such items are included (they should not be)
- Load or create a save, and start Building on an empty lot with no terrain paint (alternatively entirely bulldoze the lot if necessary)
- Select one Build item of the above type that comes with a pack (a column from City Living for instance, a platform trim from Get Together, a roof style from Island Paradise, a pool trim from Get Together…)
- Use it and only it on the lot; do not put anything else on the lot except what is needed for the Build item to be used (ex: placing a pool in order to use a pool is OK; placing a room in order to use a roof style is OK).
- Export the lot to the Gallery
- Inspect which packs are flagged in the Gallery; the chosen Build item's pack should show up, but the list of used items (using the "Show used items" button) should be empty
- Some Build mode objects will not show up in the list of used items in the Gallery. Same symptom as above, but with individual objects. We've only noticed so far the "Pink Flower" carpet rug from Backyard Stuff, but that's all.
All in all, it could be multiple problems with a large variety of symptoms that can even combine with each other :-/ Random hidden shoes on full-body career and situational outfits, synced hairstyle and make-up loosing sync with career outfits, career and situational outfits getting stuck and exported with the household, unlockable CAS parts not always flagging the household with their pack of origin, the CAS and Gallery interfaces not marking pack-specific swatches the same way, unlockable and crafted items not always flagging their pack of origin, and architectural elements other than doors, windows, floors and wall coverings which flag the pack without appearing in the Gallery. There's unfortunately quite a lot happening here :-(
EDIT: Typos, clarifications in the different "How-to"s, more typos, grammar, touchups for some observations.