Oddly enough, I have a 2023 datapoint on this as well.
1/1/2023 - Booked a prepaid FHR stay
1/3/2023 - Cancelled FHR stay (change of plans)
1/5/2023 - Received $200 Hotel Credit
Edit
2/12/2023 - Booked a prepaid FHR stay
As of today (1/30/2023) my account is still sitting at negative $200, as I expected this credit to be correctly clawed back. I have the remainder of the year to make a qualifying stay. Of course the terms have explicit language to address this...
Statement credits may not be received or may be reversed if the booking is cancelled or modified.
So this is not some sort of loophole that can reliably be exploited.
Edit: I ended up booking another FHR stay on 2/12 so my "datapoint" is only good for a month or so, but Amex did not clawback the $200 credit I received based upon my cancelled 1/1 booking