TheBeatlesPkmnFan42

I was working on a build in Creative, and I went to change my game mode to Survival for a little bit (I was wondering if something I wanted to do required me to be in Survival) and when I typed "/gamemode 0", I got the message "Format error: Your game mode has been updated to %s". It still successfully switched me to Survival regardless. I switched back to Creative, and it says the same thing. I tried searching both Google and these forums and couldn't find anyone else having this problem. The problem only happens when I change game mode via chat, it doesn't do it when changing it via NEI.