Gallery "missing items" errors increasing when downloading multiple lots

Context:  I ran a shell challenge (#littlecastlechallenge).  I own every pack/kit/all but 1 maker kit.  None of these builds use CC.

I was going through the entries and I kept getting the "missing content" message... except after the 3rd or 4th placement of a lot (different lots), it'd go from 1 item to 24, then 79, then 81 missing items.  The main screen in the gallery shows I own everything needed for the build, and as above - I do own it all.  I double checked that everything is active in my marketplace/installed (it is).  

Attached:  Screenshots showing the gallery page and then the next two missing item popup messages.