Im on the quest Binding Fate where i have to defeat Fenrir. Its now my third time restarting the quest. After some time i have damaged him, he just goes underground and he wont come up. On all my attempts the same thing happens, i wont take damage when he goes underground so i have to go to my older save and start over from the beginning. On my second attempt i got him really low and then he just bugged out like the other attempts.