The image above is the x-rotation of two bones in a walk animation that should be mirrors of eachother. The animation is 120 frames long - each foot walk cycle is 60 frames. As you can see, the bezier handles on the keyframes that sit on frames 0 and 120 do not match the ones on the keyframe at frame 60.
Is there a better solution for this than copying the keyframes again before and after the 120 frames so that the curves all follow the same path in the 120 frame period? (solution illustrated below - remember, I'm only using frames 0 through 120)