Hm-m-m. I'm guessing that there's nothing to be concerned about, providing that the "stiffness" is not severe enough to strain the servo.

Did you oversize the outer most point of each hinge hole to allow for the wider flange at the hinge pin? It could just be that they are binding slightly, which will ease up as they wear in.

Did you taper the leading edge of the elevator(s) to a fairly thin line? (45 both the top and bottom.)
Dennis-