Okay so I'm back from the scavenging issue.
Tried it in SP and it indeed worked fine. However... on the server it didn't. At least I think I should've gotten one level after a day of looting.
Edit
After investigating more I noticed there are other issues with the dedicated server. NPC (Survivors & bandits) attack animation isn't show instead they are static while doing damage to what they target.
Stealth is working differently on the dedicated server. Looting, damaging stuff doesn't increase your visibility at all. I'm not sure if this is an issue in vanilla (didn't test this).
Edit 18/04
https://hastebin.com/efawofesig.sql
Seems like it happens when I select the iron spear with the inventory UI open
Suggestion: Make it so you can see the progression of the action attributes, like it was in A16.