Cannot replicate the crash

Did you try with Release Candidate 3?

It pretty much says you were located here (see image), outside the walls, and 
walked south into darkness.

How did you got there? I looked at the collision map, but it should have been 
impossible to reach there... While I could make a "cage of the cage" (adding 
collision on the map borders, to prevent this crash), you likely would be stuck 
for hours in a technically dead zone. I would need to know a bit more of how you 
walked there to find out how you got into that area to address the root cause, 
rather than wasting time treating symptoms (for no crash but a terrible user 
experience).

All crashes are considered critical issues, but given this one is hard to 
replicate, downgrading it to important instead.

Assigning to myself as this relates to content, and to act 2.

I never tried RC3. I did not go there by normal means, I used the level editor to get there, as I pretty much explored everything at this point and I was curious to see what lies there, because why not. Still, that crash was not supposed to happen, I guess.

Now after going to that spot again, the crash occurs again. If that is how this map is made, maybe this crash is not a big issue, as again, I am not supposed to go there by normal means. Let me know if this needs further testing.