Couple issues keep happening (also 1 question)

Random Missions:
After matchmaking with people I will have missions that need completed. I did not have these completed on my second time thru on tvhm but I did not select them.
Few times this has happened I also noticed they were the missions of the person that was running the group.

Matchmaking Cancel:
When in a group trying to run Proving Grounds and it’s taking forever to get us into a new one I try to cancel and it won’t.
I will go all the way to title screen and that don’t help to reset. So I have to quit and reload the forever startup of the game smh.

Question:
TVHM Reset Missions - Once I beat the story on tvhm I can then play Mayhem 3 on all the side missions. But I would like to play the main story on TVHM Mayhem 3. Worried if I tried I would have to play normal tvhm again

Thanks