Mine started to do the same (7.5fx). Take it off the bike and put it back on and make sure the bar end cap is nice and tight in there, that is what causes it to slide. I got the new bar end attachments that came out not long ago and mine never moves anymore. Maybe even change out the screw that tightens the bar end down, get a stainless steel one that you can tighten down tighter without stripping.