Magisk Mount problem / Couldn't restore a "Migrate" Backup

I created a backup with Migrate. But beeing in Recovery it reports: coudn’t mount data.
So I couldn’t restore it.
I am running in Tab S5e, with “normal” recovery, not TWRP.

Just seen: Magisk 25.2 itself already reports a few mount Error in ins protocol:
/dev/OwHKx/.magisk/mirror/vendor …and others (including data). That seems to be origin of problem