Are you using the (newish 1st July) inventory tags at all to sort your sims inventory? I updated MC Command Centre and would look and have stuff in the fridge and then I'd come back from travelling and look at the fridge again and it would be empty causing me to freak out. I'd save and quit the game and go back into a an earlier save and the "stuff" appeared again. As I was on the latest version of MC Command centre I wasn't sure why the bug deleting my inventory was occurring.
Apparently I had changed the inventory tag while I was out travelling to set it to favourite and clicked on the fridge when I came back from travelling, which then made it appear empty so I would click on every other storage box to discover it was empty (which it was showing as empty because I still had the tag as favourite) - freak out - reload an old save and keep playing from there as the stuff had returned.....so before blaming mods (like I did) make sure if you are using the new inventory feature in any capacity in your sims inventory that all the tags have been removed.....
If your tags are all removed in the inventory and the stuff is still disappearing the only other thing I experienced was the complete destruction of my bookcase books because I removed LittleMsSam's separate inventory mod forgetting that it's literally stated that will occur if you add or remove the mod from your game. So make sure to remove all the objects from the inventories before adding/removing that mod or any similar mod you might have that affects inventories.
Thought I would share because I feel like a fool not understanding until yesterday that the new inventory feature is affecting storage objects - I guess because the new sorting tags don't APPEAR on the storage boxes/fridges I just never paid attention to how I was supposed to sort things by using this new feature they launched.
Also if you have an apple as a favourite and have apples in the fridge the game does not SHOW the apples in the fridge, so my fridge under the favourite sorting option has NOTHING IN IT.
Anyway, all my own experiences with this "inventory glitch" are user error - in my case removing an inventory mod I shouldn't have removed and not realising how the new inventory feature blanks out storage boxes if you change the settings in your sims inventory to favourite which is basically the only view I've been using now apart from the default show everything.
