Changing a map name to "Map F6" Censors it completely?

So I am making a large map on the ground. But to update the maps I need a copy which is what I've been doing. Renaming them the same to make it easier for me. Map A1, A2, B3, B4 etc.. The problem comes when I type in Map F6. Once I do that, completely censored. Why? What is remotely offensive there? Am I missing some internet slang or is this a bug? Please be a bug that you will fix. I got so far in my map naming and I was almost done until I came across this hiccup. Please fix it, I beg you.. (And probably check to see if anyone other letter-number combinations censor just encase.)