I use 2013 and by default multiplicity is set to 1 so you must have accidentally set it to 3. That happens some times.

I am glad you found it. Most of the time when that happens you have to wipe the entire maya folder and start over. It's just faster then trying to find the thing that got borked.

As a general rule in the future when stuff like this happens. Exit maya and just rename your maya folder and reopen maya. This will generate a fresh prefs file with all default settings. Then see if the problem goes away. If it does (and it usually will) then you know something must have happened to the prefs.

What I do is once I have all the settings I like, I make a copy of the userPrefs.mel file. Then if things get borked I just replace the userPrefs.mel with the copy and then i don't have to waste time systematically trying to find the problem.