devtrackers.gg
So, I have loved this game more than any other I have played in the last two years, 150 hours in, and I get to the Fenrir fight in Jotunheim.
I didn't have any problems with Fenrir staying underground, as has been reported on these forums elsewhere.
Two-thirds of the way into the fight, Fenrir just leaps out of the fight zone and a marker appears at a different location on the map. Any attempt to fast travel out of the fight zone leads to an endlessly repeating death cycle as you are respawned to the same fast travel point and have to revert to an earlier save. But there's no point doing that either as there is no way out of the fight zone, and no way I recognized of getting out of it to pursue Fenrir to wherever it is that he has gone.
This bug has ended this game for me and I hate that it will be the memory of the game that lasts the longest. What I hate more than anything is that I wanted to continue playing it! Just a crazy situation.