Is the Level 5 Easy Common Exploration quest Cave Diving still available in Overseer? I haven't seen it on my list of available tasks in over a month. For every level and skill there are 4 common tasks, but for Level 5 Exploration there now appears to only be 3.
Looks like the quest is back after taking a month off after the August patch. It appeared after the first quest rotation after the September patch. So whatever was broken is fixed now.
This is still happening to me. I log out with 5 active overseer quest running. 10-12 hours later I log back in to only 4 on my list. The missing quest never reappears.
The OP's concern was specifically in regards to the availability of the Cave Diving quest. He was concerned that it was missing from the rotation of available quests but followed up saying that it had returned to the rotation. It sounds like your issue is that your active quests are going missing. I suggest looking here instead: https://forums.daybreakgames.com/eq/index.php?threads/overseer-quests-disappearing.266630/
Send a like to the first post on the existing thread, and add on there. https://forums.daybreakgames.com/eq/index.php?threads/overseer-quests-disappearing.266630/