I’m not arguing that his FTP “is or is not” correct, I’m more on the stance that he is taking a different approach to training.
We also are not sure what workout he was doing, Xert uses a lot less SST than TR - he could be very unfamiliar with these types of workouts and a repeated 85-95% workout drives his HR up as he progresses to the point of sickness.
Sidenote - its an interesting read that has been discussed on THIS THREAD about what causes nausea when working out. I learned a lot from it.