What's "wide dynamic af"? My Z8 has dynamic or alternatively, wide areas but not a "wide dynamic". I'm sure it's some misunderstanding or typo? Also, he claims that the Z8 followed the subject in spite of the player moving behind a net. This doesn't happen reliably in my experience.
As an aside, when folks say send your camera in, it makes me chuckle. I have two Z8 bodies, both of which have difficulty maintaining subject lock and tracking (worse on birds in certain scenarios which I've described) and both of which exhibit the strange af on people as you've illustrated. What are the odds that all of these bodies are defective? There is an interesting thread on DP from a pro who shoots runway, where his Z9 was, inexplicably unable to maintain consistent eye autofocus during the model shoot. Some attributed it to the lighting, and while that is a possibility, I've experienced it natural lighting/flash as well. When shooting portraits, I frequently find that it grabs something other than the eye in spite of it indicating eye tracking, and occasionally, it focuses on the lash, brow, or elsewhere. I find myself shooting dozens of redundant frames knowing that some may be in critical eye focus, others won't. I have simply come to the conclusion that for certain applications, the Z autofocus just isn't as good as it should be. In my experience, it's fine for perched birds, most BIF, the best for aircraft, good for motor sports, equivalent for most wildlife, but hit or miss for people. Likewise, with sports, I've come to the conclusion that my R3 just focused better, easier, and with less angst.