I just finished the first dungeon on heroic difficulty. As soon as I stepped out, the game crashed and put me back at the PS4 dashboard. When I started the game again, it said my save file was corrupted at the start screen. As far as I can see, my only option would be to restart the game from the beginning, losing everything I did for the past several hours.
This is very upsetting, and very unfortunate since I was really enjoying the game. I do not feel like starting from scratch again as I had made good progress and this has left me feeling a bit bitter.
I hope this makes others aware that your save can be corrupted randomly at a whim it seems. I literally took the exit portal after a tough dungeon boss and my save file is gone.