Using Migration Assistant to an external SSD under Sequoia

Problem using Migration Assistant to an external SSD under macOS 15.1.1

I have a Mac Studio with an external SSD. I booted macOS 15.1.1 from the Mac Studio's internal SSD. I created a new empty volume in a container on the external SSD. (There are other volumes in the same container, but I have no reason to believe that is relevant.) While running macOS 15.1.1 booted from the Mac Studio's internal SSD, I ran a full installer to do a clean install of macOS 15.1.1 on the newly created empty volume on the external SSD. The installation appeared to be completely successful. I hadn't used the Migration Assistant as part of the installation.

I then booted the Mac Studio from the macOS 15.1.1 I just installed on the external SSD and logged in as the administrator. I ran the Migration Assistant program to migrate all the users, applications, system settings, etc, from macOS 15.1.1 on the internal SSD to the newly installed macOS 15.1.1 on the external SSD. The migration appeared to run successfully to almost the end. It rebooted the Mac Studio and displayed the following message:

Migration Complete

A restart is required to finalize your migrated settings

Your migrated data is ready to use following the restart

Your computer will restart automatically in <countdown> seconds

There were two buttons: A disabled "Back" button and a "Restart Now" button

After it restarts (either as a result of the countdown going to zero or because I clicked the "Restart Now" button), it displays exactly the same message. It is in an infinite loop of restarting. The only way that I could get out of the loop was using the Power button to shutdown the Mac Studio and then hold down the Power button so that I could select the startup volume on the internal SSD. I successfully ran while booted from that volume. When I used the "Startup Disk" function to select the volume on the external SSD and restarted the computer, it went into the Migration Assistant infinite loop again.

Do you have any suggestions? If I boot into Recovery, is there anything that I can do so that Migration Assistant will complete successfully rather than going into an infinite loop? Is there anything that I can do to prevent it from going into an infinite loop, even if it hasn't completed successfully?