Deadlock Detected Error

I've played the game for most of the day, but since the most recent patch (0.4.0c), I've been getting a Deadlock Detected error and the game hard crashes. It has been happening roughly every 5 minutes (or sooner) from the time I load my character.

If it helps at all, I've been playing with Proton experimental and/or hotfix since the game launched. I've also tried verifying Steam game files and changing video settings.