/gamerule GameLoopFunction bugged out in 1.12.2

I'm trying to finish a map project before I move on to the snapshots, but a bug has been occurred, stopping me from looping any function. As you can see from the screenshot, the gamerule itself seems to be bugged out, showing up 2 separate gamerules when tab completed. I'm not able to tab complete functions as well, contrary to /function, which I can. This not only whappens in one world, but this happens in fresh new worlds as well.