No matter where they are in the world, when players create a map it shows up like this:

In the End (which is not a TC world) this is what it looks like:

Latest TC build. This doesn't happen on a server without TC installed.

Any idea when this might get fixed?

I'm going to take a look at this (never looked into biomebundle's source before, but this is the kind of issue I enjoy digging into). I recognize that texture as the texture used for maps made in the nether, so that will help when debugging.

OK, first update: this only happens with the bukkit version, not the forge version (or if it does happen with forge, it doesn't happen in single-player). And confirmed for 2.8.2-SNAPSHOT.