An example is the cave in screen 21 of Molka's Overworld.
It only seems to happen with overworld caves, in Special Item rooms.
(816) Special Item Rooms in Overworld Reset themselves
Special Item Rooms... in Overworlds.
Easily fixed.
Would like to report that variations of this bug still exist in build 819.
Variation 1 exists as a compatibility issue with quests made in 1.92 and 2.10. These quests, when played in build 819, have respawning Special Item rooms.
Variation 2 effects the "Red Potion or Heart Container" room. Quests made in 1.92, 2.10, and build 819 have these rooms respawning as well.
Example quests can be found here, titled according to the version they were created in: www.rphaven.org/rsc/zc/bugs.zip
When you load the quests, screen 00 is the Special Item room; move to the right to get to screen 01, which has the Heart Container room.
Also, Feed the Goriya rooms make the guy reappear, but he won't go away even if you give him food.