This seems to be a issue with the subclass NPC module. It seems it requires editing of the core code for it to work.Sorry up front for the insanely long post. I felt it was best to document this as thoroughly as possible.
I've been having increasingly severe issues recently, where aspects of my character are reverted or outright forgotten. These problems roughly started happening when I used GM commands to give my character access to every vanilla profession (Herbalism/Skinning/First Aid/Cooking/Fishing were all learned legit), and used the repack's subclass NPC to purchase proficiencies in every equipment (I play a Druid, also this didn't end up working). From then on, more and more severe issues have cropped up more and more frequently.
As far as I can tell, these are all the issues I've encountered:
- Quests I've completed reappear in my quest log after relogging, with varying degrees of completion. The quests affected seem to change, and I can't find a pattern for what's affected other than "more recently completed quests might be affected". If one of the quests only requires turning in to "complete" it again, this will give the typical rewards again, but won't preclude it from once again reappearing in my log later.
- Achievement progress reverts without warning; most notably, the Explore Stranglethorn Vale achievement removed the Mistvale Valley discovery criterion after I'm positive I'd earned it, and it refused to readd it when returning to the location. The achievement is functionally complete, but cannot actually be earned since the one location it reverted can't be discovered again.
- Skill progress toward professions and weapons gets reverted when relogging.
- Armor pieces I'd recently equipped will sometimes be reverted to what used to be in those slots when logging back in; so far, this has happened with shoulder armor (replaced with my previous armor) and a trinket (the Arena Master trinket, which despawned and left nothing behind since it was my first trinket). Items will do this too, replacing themselves in bag slots they were last in before they left my inventory initially (or, if they were moved to another slot, back to the previous slot).
- Worst of all, leveling up to level 39 when turning in quests in Booty Bay caused nothing to happen, and my level just rolled over to the start of level 38.
It's clear to me that there's some kind of database corruption or rollback messing up my character, and it seems nearly exclusively tied to the act of logging out and back in. Unfortunately, not only do I have no clue at all about programming, I'm also extremely new to WoW private server stuff (honestly, I haven't played the game at all since 2008, and I only got an itch to try again because of your repack!), so if there are relevant logs to pull, I don't know where I'd find them or what they'd even be without help. I'm having a lot of fun reliving decades past, though, so I'll do anything I can to help with diagnosing the issue.
I did see that these error messages in the worldserver window display whenever I log in; I think they're a product of the NPC subclass guy and maybe why it didn't end up working?