Great bug report. Really made it easy to follow and notice the issue. 
It does indeed look weird on the de jure mapmode if the title no longer exists. I'll be sure to file a report of that.
The borders however, I think are more of an issue of not being properly updated when you first create your custom kingdom. So it won't be updated until after you save and reload the game, and instead uses the previous border until you do.
It does indeed look weird on the de jure mapmode if the title no longer exists. I'll be sure to file a report of that.
The borders however, I think are more of an issue of not being properly updated when you first create your custom kingdom. So it won't be updated until after you save and reload the game, and instead uses the previous border until you do.