Thanks for the continued troubleshooting. I'll have a release soon, probably near the end of this week, which will include the workaround of putting quest markers on top of an object. That workaround is believed to avoid the problem. I've made that change to every POI in my modlet.
Glad you've found an apparent workaround. I finally got to Tier 4 quests from the trader in this play through.
1) accept quest for clear zombies at NTT_HQ_01
2) go to quest marker location. quest marker is ~ 10m below the surface, but it is not visible when flying underground.
3) cancel the quest from my queue.
4) keep visiting Trader until this POI shows up on the list again. I did other quests in the mean time. So I did not invoke the admin reset quests this time of testing.
5) accept the quest again.
6) quest marker is now visible underground. activated and completed quest, returned to Trader and got my reward.
7) took on some other Tier 4 quests in the mean time until the NTT_HQ_01 POI was listed again.
I performed the iteration of steps 2) to 7) a total of six times, all with the same result:
a) quest marker
location is always below the surface, in the same place.
b) quest marker is
not visible underground until it is deleted from my queue, accepted again from Trader and
then it is visible in godmode underground.
c) completing quest will allow the quest to be offered again at some point. But it will make the quest marker invisible again.
But it is a two-step process. Initially the game will not show the marker underground when flying down to it. Delete from queue, accept the task when offered again. Quest marker will now be visible underground (godmode) and can be activated, the quest completed and returning to Trader for reward. Rinse and repeat.
Thats about all I intend doing on this pet project. Don't know if my observations were helpful, but I did learn to use some in-game tools that I normally wouldn't have reason to access. Thanks for the POI's - keep 'em coming!