Instead it just changes to None. It is not a new problem, here are a few reference to others asking the same:
It’s not a massive issue if you know the source of the problem, but if you rename a map in the content browser and it’s one of the default maps in the maps and modes section in the project settings, whenever you launch the game, it crashes the game...
Hey guys, Not a major bug but sometime still to look at. If you rename the map that you are currently in and its set as a “Game Default Map” or “Editor Startup Map”, it will not reflect the new name change on the next time you run the game or...
This was a logged issue once. Why was it marked as “Won’t fix”? Is it unnecessarily hard to solve?
Hello CrimsonHawk,
I will be closing this thread as a duplicate. I will be responding on the thread that you linked above. However, please refrain from creating duplicate threads for tracking purposes.
Make it a great day