Domain Transfer - Faulty Whois NS server

Hello together,
I've transferred a bunch of domains to OVH without much trouble, but the last domain transfer resulted in an unfixable status for this domain and support is not getting back to me. Maybe someone has an idea.

The domain is fully visible using the OVH Manager Web UI, i.e., DNS and Domain overview are visible and usable.

* The WHOIS entry is still listing the previous NS servers from before the transfer, but the change date and time have changed to when the transfer occurred. So OVH actually made changes, but not the correct ones.
* Using a "Reset DNS" results in
"An error has occurred requesting the DNS server reset. (Your domaine nsType is already 'hosted')".
* Enabling DNSSEC results also in a failed state.

How can I correct the WHOIS entries? Could the API help?
Thank you for any ideas!