Hi, This bug was reported against Xen 4.8 (which is out of support and out of security support now) and there has not been any activity for over almost two years.
I'm cleaning up old open bugs, and I will close the issue now. If you found a solution to this problem, please let us know, so the information is added in the bug report for anyone else who might run into the same situation. If the problem still persists with Xen 4.11 in Debian stable, please reply and reopen. Thanks, Hans