Hi, in case it might help other Live systems still using aufs for some reason, for the record I've implemented a workaround to this bug in Tails:
https://git-tails.immerda.ch/tails/tree/config/chroot_local-patches/live-boot:_workaround_aufs_bug.patch?h=feature/14976-linux-4.14%2bforce-all-tests (the only downside I've noticed so far is that the Plymouth splash screen disappears as soon as the bug is triggered, and the boot messages display is corrupted by the kernel bug message and call trace) Cheers!