Yes, it's a related problem: in the initrd (i.e. before resume or before
mounting the root filesystem), LVM tries to activate only the root
partition and the swap partition. It seems more harmless to forget to
activate a partition than to accidentally activate one that shouldn't,
but in any case, that's what the lvm2 initrd script tries to do. So for
resume that will only work if this script is able to find your swap
device. In the case of uswsusp, that fails because the name of the
device is in /etc/uswsusp.conf which lvm2 doesn't check, and in your
case it fails because there's no easy way for lvm2 to find which volume
has the given UUID (the easiest way would start by activating them all,
which of course would defeat the whole purpose).
Stefan