It looks like the Qubes devs managed to fix this in Xen 4.6 last year: https://www.mail-archive.com/xen-devel@lists.xen.org/msg75655.html
Can someone investigate this bug? Not being able to restore saved domUs is a major roadblock. It's been three months with no response and no movement on this issue. Thanks. -- Mike Edwards | If this email address disappears, Unsolicited advertisments to | assume it was spammed to death. To this address are not welcome. | reach me in that case, s/-.*@/@/ "Our progress as a nation can be no swifter than our progress in education. The human mind is our fundamental resource." -- John F. Kennedy