When leaving a group the previous dungeons won't be reset, but they won't be available to the player either. Hence they sorta count as being reset.

Currently the addon flags the instance as reset immediately. If the player is inside, this should be delayed until the player zones out.

If the player doesn't zone out within a minute (or check forced zone out message) assume player now owns the instance and do not flag for reset.

If the player rejoins the party figure out if the player has rejoined the old party / instance owner.