Dear Bethesda.

I have come across a very bad bug wich breaks the game bad.
i was freeroaming the other day and cleared dungeons without having the quest for it. I got a few quest items after completeting the dungeons.
But when i finnaly got into a city and got the quest for the dungeon i already cleared i couldnt turn in the quest. The quest marker kept marking the treasure chest . Since i already had taken everythng in the chest the quest whas bugged.
One quest for example is: The legenday scourge Book .


I hope you guys look into this becouse this bug is just absolutly ridiculas