

I am not 100% sure of how it works, but you sometimes will get teleported directly to the party mid dungeon. Regarding teleporting to a dungeon in progress. Players run dungeons differently, take alternate routes, skip patrolling trash packs etc, so for a new player, it can certainly catch you out. It might appear that trash re-spawns, however it is more likely that this trash pack has been skipped by the group. In dungeons these days, the chance of a 2 hour + run are minuscule, so it just isn't seen any more.

Therefore if you kill a boss post trash, that trash will no longer be able to spawn. However it is usually 2+ hours and it is often tied to bosses. I am pretty sure that trash still has a re-spawn timer.
