I have moved this post from Whonix in live mode in Qubes OS! Amnesia and anti-forensics mode - which is about Qubes - to here, its own dedicated forum thread, as the grub-live implementation is totally different.
Upstream of file /usr/lib/dracut/modules.d/90overlay-root/overlay-mount.sh is: GitHub - dracut-ng/dracut-ng: dracut - the event driven initramfs infrastructure
Could you please suggest and/or contribute this change there?
See also:
grub-live, Developer Information