Bricked save file

I am back in. reinstalling/taking time away from it got me back in

it did it again fighting the mighty silverback...why is this happening where it breaks my save file at this checkpoint.

I have discovered that if you completely shut down your Xbox and then restart, you will be able to login successfully with your character at the Waypoint inside the Mausoleum. You can then port out.

Also, I managed to get to and defeat the boss on my witch using only Firewall and Spark plus 2 skeleton warriors from a Sceptre. I'm sure it was probably just dumb luck but FYI if it helps anyone else complete the Mausoleum.