This is what happen when i crashed back to the desktop for no apparent reasons during my mission earlier today. Before crashing the mission was 75% completed.
1st thing : When i came back, all the monsters i killed before were back but the mission was still at 75%.
2nd thing : I reach 100% mission completion but the dungeon was still 75% full of monsters.
3rd thing : Proceed to kill all the monsters i already killed before the crash and noticed i was getting the same loot again ! I end up having everything in double !
4th thing : All the chest were back too, same thing happen with the monsters all the loot i got before the crash was there again.
This must be known already but i just want to be sure you're aware of these bugs.