I'll hazard a guess for the cause at the ol' P factor torque effect that the Mooney is allegedly famous for, especially on T & G ops. Probably using RWY 14 would be the best bet as to how it ended up there, and going by what was said by some of the people on site. Quite a few of them seem to have ended up off the side of strips on takeoff/go around.
I was told when I was converting on them that they bite if you don't keep up with them but I've never had any concerns or really noticed any great predilection for them to go off track on the power up or go around. Maybe because I use the pedals for the reason they are there. I've actually noted more of a want to go to the left in a GA8 turbo Airvan.