It could be my resolution that's the problem, 1366x768, but it's the same map as it always was and this has never happened before, so I might as well report it.
Anyway, picture shows the entrance's graphics messed up. I think I was scrolling up from the bottom when it happened. You can still move, it doesn't make it so you can't move the screen, so it's no big deal.
(For bug-finding purposes, it would be nice if there was a command that gave you the name of the map or something.)