What I was expecting to happen was:
The display of the world would be the same when I log in the world.

What actually happened was:
It displayed the wrong gamemode on the save menu.

Steps to Reproduce:
I'm not sure how this was reproduced , but I think it runned in a server on gamemode 0 (survival) and when I logged to the world (Single-Player)I changed to gamemode 1 (creative), but it didn't updated.