Cannot keyframe tracker path Center X/Y, creates new path.

I have a Fusion paint node with grouped clone strokes that aligned using a tracker path created within the same node. I want to adjust the Center X/Y of the tracker path at certain frames so I click Center X/Y keyframe button... but it creates a new Path in Modifiers. i.e., I click Center X/Y of Track1TrackerPath, and a new Path1 is created. I would have expected Track1TrackerPath keyframe button to turn red, allowing me to keyframe the tracker path's center.

Is this not the correct way to keyframe the tracker path?

Thanks,
Ashley