this is the setting I'm referring to. it's present in all the packages I'm familiar with, whether 3d or 2d/3d hybrid, I've seen a similar/comparable setting in each. The blurred shots were all rendered from frame 1 with the settings underneath.

The first blur had -1, 0. The second had -.5, .5. The third had 0, 1.

Since the renderer was sampling from different parts of the timeline to generate the blur, each shot the ball appears to be in a different part of the frame. Applied to tracking, assuming the track looks fine rendered w/o blur, and looks out of sync when rendered with, my thought is simply that for this shot, it may lock back into sync by adjusting those settings. The theory can be partially tested by comping the matchmoved shot with the blurred render and shifting it 1 frame earlier and or later, and seeing if it improves. If it does, then it's gotta be that setting. If it doesn't, it could still be that setting, since 1 frame could have been too much of a shift (sometimes I need to only shift motion blur sampling by 1/4 of a frame depending on the nature of the shot, but I haven't learned yet how to intuit WHEN that's the case).