When changing the name or moving the location of a custom game mode blueprint that is set as the "default game mode" in project settings, the default game mode is reverted back to the prior game mode. The custom game mode is still shown as the default game mode.
Results: The default game mode reverts after moving or renaming the custom game mode blueprint, but still appears in the as the default game mode under Project Settings > Maps and Modes
Expected: The game mode to remain after renaming or moving the blueprint to another location.
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-80948 in the post.