Comment # 2 on bug 1186943 from Ludwig Nussel

There's
ID 435 gen 211403 top level 434 path @/.snapshots/46/snapshot/var/lib/machines

I guess that comes from systemd-container's %post calling
/usr/lib/systemd/scripts/fix-machines-btrfs-subvol.sh. Might be incompatible
with transactional mode.