Since I got no help here, on a hunch, I reinstalled the FUSE filesystem
$ sudo apt-get reinstall fuse
and a reboot seems to have solved the problem.
ubuntu mate 21.04 USB stick will not automount
Since I got no help here, on a hunch, I reinstalled the FUSE filesystem
$ sudo apt-get reinstall fuse
and a reboot seems to have solved the problem.