[GALLERY] 'Content not installed' warning with all content owned

Having this issue ever since the marketplace was introduced. I am in the middle of building a new save, so I am uploading lots from my own game into my library, then downloading them into the new save. Clearly I own everything because I'm saving lots I built from scratch (no mods, no CC), and I'm downloading them into the exact same game on the same computer. But I'm getting the "Content Not Installed" message!

At first I thought it was just an annoyance because the lots seemed to install okay despite the message, but now as I'm playing the lots, I'm noticing that the game has replaced some items from packs I own with random base game items! 

So if I load the lot in one of my old saves everything is where it should be, but if I upload and install that same lot in a new save, a lot of items are replaced with random base game stuff! 

And yes, I have checked that all packs are activated, I've done a full uninstall/reinstall, I've cleared the cache multiple times, and everything else I can think of. Nothing fixes it.

Research indicates that there's a massive tagging problem on EA's end that might be causing the issue. I haven't found evidence in build mode yet, but I have found numerous tagging problems in CAS since the marketplace update that weren't there before.

For example, a pair of boots that is available to both men and women in the Everyday category. I try to find that same pair of boots for Party, or winter and it just won't appear for women in those categories. I can deselect Party or Winter from the sorting tab, but the boots still don't show up. I have to deselect the "female" tab to get them to show up in the party or winter category -- despite the fact that they ARE available for females in the everyday category. 

It's happening with loads of things, outfits, tops, pants, etc. I am building a new save so I am in CAS a lot. It's annoying and I think it may be the root of the bigger issue. 

Yes, I know I can just put the boots on in everyday and then copy them over to party and winter. That's what I do to get around this issue. But I do think this new problem that I've never encountered before might be what's causing the lot downloading issue as well. 

For example, I redecorated the lounge in Del Sol Valley. It looks great in my old saves. But when I upload it and then download it into my new save, suddenly the coffee tables and the tiny lamps on them are base game ones instead of the expansion pack ones visible in my old save?! Could it be that the game isn't recognizing any items that aren't tagged as "lounge" items? The way it seems to be filtering out boots that aren't tagged as party or winter items?