In the console, I select an npc, and then type INV

I get back a response that looks like this:

Kings Gang Member (0011849A) has 6 items:
1 - Kings Outfit (00110A74) (50,500.00%) - Worn
6 - Case, 10mm (00140AA7)
13 - 10mm Round (00004241)
1 - 10mm Pistol (0000434F) (36,45.00%) - Worn

I can repeat the command and I still only see a list with four entries.

I am concerned that somehow the inventory list might have been corrupted. Perhaps item counts are negative, perhaps the bogus items belong to a missing mod, or perhaps they are in the process of being destroyed.?

Does anyone have any suggestions for figuring out what has gone wrong, here?

Probably just leveled lists. If it's not causing any problems, why does it matter?

Well, that is the question, is it not? When I am experiencing problems what are the causes of those problems?

So... yes... when I am debugging, I become extremely paranoid and suspicious.

And, while this might be leveled lists, in other contexts I would get a formid for the leveled lists in inventories. They would not have names, but with the formid I could look them up and see that they were leveled lists. In this case, I was not getting any such formid, which makes suggests it might have been something else.

Also, when I pick pocketed 1 unit of 9mm ammo into their inventory, the count of items in their inventory went up by 2. When I removed it, it went back down by 2. When I pickpocketed their 10mm ammo, their item count went down by 1.

But, also, even if the information is not immediately relevant, I have found that having a detailed mental model for "how things work" can help me when I need to deal with related issues, later on.