I think I've been experiencing the same issue on my dedicated servers.
I normally play SP with most loot at extremely rare, but it seems I'm finding at least more food than usual on my MP servers with the same settings. I want to say meds are also bugged, but in some loot spots you find what you would expect, but others it's seemingly overflowing. Same thing with bullets.
The rest seem to check out, with the exception of books and crafting materials as I normally keep those at 'vanilla' or slightly more than. So I can't give a good gauge on what I should be finding on extremely rare.
