Just had this happen....again. (PC). Think I've actually had more hard crashes in this actvity than I actually have legendary completions. At least 90 mins today alone completely wasted. To clarify, there appears to be a few sepate issues, some people mention error codes. The crashes I've had have all just been hard crashes, no error code. Game just decides to freeze for a few secs then closes itself. This happens on normal (it happened on my very first run when I logged in and got put in the activity automatically) and legendary runs, though from experience I'd say it seems to happen more in legendary runs. It does not seem to be tied to the enemy type. I've had it happen on several different enemy types. I hope this gets fixed asap because right now it's just a literal waste of time trying to farm this activity.