I have an Ultegra front derailleur for an ultegra triple crank that I am constantly having issues with. It is only 2 months old and it seems that every time I go out for a ride at about mile 20 it starts slipping. I can't shift into the large chainring, and am sometimes stuck with only the middle ring. Most times I can do a roadside fix to at least give me the middle and the bottom. I get home, throw it on the bike stand and can fix it where it works fine on the stand, but again 15-20miles into the next ride same thing happens. Anyone else have this issue or heard of it? Help!