Update: The problem occurred again with the changed firmware, so please ignore my earlier message about the firmware.
I will run with the older 6.5.0-1023-oem for now to see if it works.
Others with similar hardware might find this of interest:
https://bugs.launchpad.net/ubuntu/+source/linux-oem-6.5/+bug/2069357
Especially the note that "6.5 OEM kernel will be retired soon."
Hope this helps someone.
Update: The problem occurred again with the changed firmware, so please ignore my earlier message about the firmware.
I will run with the older 6.5.0-1023-oem for now to see if it works.
Others with similar hardware might find this of interest:
https:/ /bugs.launchpad .net/ubuntu/ +source/ linux-oem- 6.5/+bug/ 2069357
Especially the note that "6.5 OEM kernel will be retired soon."
Hope this helps someone.