Can't run Leap 15.3 as PV guest on Leap 15.3 xen server

On Leap 15.3 xen host I installed a Leap 15.3 guest from iso. It boots and runs well as hvm, but when I change from builder=“hvm” to bootloader=“pygrub” boot fails with:

bootloader failed - consult logfile /var/log/xen/bootloader.38.log
contents of the log file:
Traceback (most recent call last):
File “/usr/lib/xen/bin/pygrub”, line 958, in <module>
raise RuntimeError(“Unable to find partition containing kernel”)
RuntimeError: Unable to find partition containing kernel

As far as I could figure out from documentation running OpenSuse as pv guest should be possible without changing it.

Thanks in advance