Comment 10 for bug 2041739

This really needs to be fixed as a high priority. After 5 years, suddenly my server could not boot anymore because of it and it's unclear what changed because I have been taking snapshots of the same root pool for years.

Not sure whether 22.04 can upgrade to GRUB 2.12 or the patches should be backported to 2.06:
https://git.savannah.gnu.org/cgit/grub.git/log/grub-core/fs/zfs/zfs.c

According to this comment 2.12 should work:
https://github.com/openzfs/zfs/issues/13873#issuecomment-1889885090

Meanwhile, if others are having issues, try the portable version of ZFSBootMenu, it saved me (and I also moved to ZBM permanently, so much better than GRUB):
https://docs.zfsbootmenu.org/en/latest/guides/general/portable.html