Maybe its because your saddle didn't match your bar tape? Good to know you didn't crash and burn.. that looks like it could have been a bad one!
PS. I have some campy alloy dustcaps screwed into my old shimano cranks, and the 5mm allen key hole has totally stripped, its almost flush with the crank arm, and its in there pretty tight. Suggestions? The reason I want to remove it is so I can tighten my BB which has been slipping slightly. All I can think to do is drill some little holes for a pin spanner which I don't own, or jam a 6mm torx key in there which I also don't own, or laboriously file out a slot and take it out with a flathead screw driver which I do own.