Actually this is a general bug not only in Sastasha, if you dont discover 100% of the map on first run it wont update the achievement the next runs you do. Most people had this issue with Sastasha due to people skipping some rooms in the middle for faster runs while in the other instances they mostly clear all of it.

The crash has nothing to do with this bug, it just made it so you basically "didnt" clear the whole map on your first run.

I hope this gets adressed soon as most people are completionists and this is a bummer.