it happen to me too it's a bug you stuck there and cannot leave until you are dead and start again and stuck again it's a very bad bug

I got the same problem

Sorry for the Necro, but just in case someone still playing in 2019, the only way over found to compete this once you're stuck at the shrine is to cheat. Ctrl f4 windows or Ctrl shift f4 Linux to kill all the mobs. Seems if you don't clear every single mob before going to the boss, you'll get stuck or maybe there's mobs in the wall somewhere, I dunno. The cheats Kill everything and then allows me to finish. I didn't have a recent save, so I exhausted all options trying to salvage this ;). Gl!