Originally Posted by
Goldorak
Also, did you ever experienced the following situation : hotel appears unavailable (fully booked) on Accor sites/App (not that I don’t even have the possibility to book with availability guarantee coming with Diamond status) while the hotel is bookable via 3rd party sites (e.g. Amex travel). Really weird.

If Amex is showing you availability for a published or qualifying rate (e.g. Amex FHR), then that is an error.
If Amex Travel is showing you a non-qualifying rate, then it's possible that this is indeed correct since Amex may be accessing bulk purchase space i.e. similar to how Expedia sometimes books large blocks of inventory and then re-sells it on its site).