So I was running a few Gianthold walk up quests this morning before the maintenance window and I notice that stat damage was not diminishing over time. So, specifically two cases: 1- I got hit with the disease from Rakshasa in Cry for Help that did -9 wisdom damage and it persisted through the rest of the quest. I purposely did not heal to see if it was going to diminish (since I had noticed it was taking a long time to go away) and it never did. I finished the quest then went back to the shrine to see if that would fix and it did. Case 2- Feast or Famine. I got hit with -19 con damage from poison spell. Same thing as the other where the stat damage did not diminish over time. This one I let it go for a few mins and after nothing happened, I hit a shrine and it healed.
In terms of data: Lvl 24 character, Feast of Famine and Cry for Help, Reaper 1 or 2 (cannot remember) running solo (no hirelings or whatever) and it was from disease that lowered wisdom (mind something or other) and poison that lowered con.