Updating 11.1 to 11.2 fails on external SSD

Hardware: Mac Mini M1 and Thunderbolt 3 to NVME SSD

I have an external 500GB thunderbolt 3 to NVME SSD, and everything runs fine, the update works fine until it's time to reboot.

Once the reboot is required to finalise the update, it gets stuck on authenticating the user, it will not accept the correct or any password.

Updating from 11.0 to 11.1 refused to update the external SSD and I had to update the internal SSD, then make a fresh install on the external drive, which means I lost everything I had installed.

It looks like I have to do the same for 11.1 - 11.2.

Does anyone know how to update the external drive?