Steve, ref #332, yes that is what is disconcerting. I tried different Focus Tracking with lock on, and it appears contrarian to the Olympus M1X. viz:
https://onlinemanual.nikonimglib.com/z9/en/15_menu_guide_04_a03.html
I'm used to the 3D style tracking using Wide-area AF (C1) or (C2), that follows the theoretical tragectory of the moving subject.
The [Focus tracking with lock-on] fails, but slightly better when set towards quick "1". I would have expected delayed "5", to keep track and not quickly search.... I need to listen to Mark Cruz on Nov 10th. It's should be a courtesy to listen in if requested by a Z9 owner, ... at least to know that it's futile to resolve at this juncture - rather than wate time trying to solve the problem. I'm not amused.... what is worse, is that when locked on, and I see that in NX Studio focus point location, it will blur for no reason on one frame while the red focus point is still following. Sharp sequence, then pop blurr >> next image back in focus. I do shoot at 20fps 1/1600.
A side comment. Focus is AWFUL in the rain.