Originally Posted by Crisses
2) I thought the reason some items end up in there by the shop is that the shop thinks the item is so special that you MIGHT be interested in it.
No, that's not what happens. The items I've found populating these slots were marked as unidentified and exhibited the same weird behaviour as the other "fake" items mentioned in this thread.
It's definitely related to that bug. I guess those slots are just the next ones in line once the "Essential Components" have been filled with garbage.