Game Mode in creating new world gets locked after switching its World Type from Debug Mode to Normal.

The Bug

I switched the World Type to Debug Mode somehow, and switched to Normal, then I set its Game Mode that not the previous.

I did as in this video, and I found the Game Mode reset back to what I set that before switching to Debug Mode.

 

If the video doesn't work, try this then, thank you.
https://streamable.com/81x4qw