From what we've gathered so far from reports from other developers and reports we've gotten from players, this looks to be a bug in the Unity engine code itself.
It seems the issue occurs on Windows systems specifically.
The error is that the engine/game is attempting to access an invalid address in memory.
For some, this is something that occurs once at a random point in the game and after a restart of the game, it's not seen again.
Others are seeing this happening frequently, either at the same or multiple specific points in the game.
We're currently awaiting response from Unity and other developers with potential workarounds or explanations to specifics surrounding the issue.
Please keep the reports coming and we'll hopefully get to the bottom of this soon.
EDIT: Some Steam users have reported the issue being fixed after disabling the Steam Overlay. If you're playing through Steam, please try to see if this resolves the issue.
From talking to other developers, we know that the issue can occur on non-Steam games as well, but it might be worth trying if you're on Steam and it's stuck in a loop where the game crashes at the same point every time.