Desabilite e desmonte os diretórios
systemctl disable mnt-pve-testdir.mount
umount /mnt/pve/testdir
Remova as montagens
nano /proc/mounts
Remova do systemd para que não remontem no reboot
rm /etc/systemd/system/mnt-pve-testdir.mount
reboot
systemctl disable mnt-pve-testdir.mount
umount /mnt/pve/testdir
nano /proc/mounts
rm /etc/systemd/system/mnt-pve-testdir.mount
reboot