Items Removed Warning?

I had this message too. At first it was popping up almost every time so most likely a bug. Then it popped up when there was a problem with HSY extra items from pre-order and they were missing from my own builds. That bug was later fixed. But now it’s again a warning that shows up sometimes (rarely actually), but nothing is really missing. I have all packs, except for few kits and Cottage Living and Eco Lifestyle.