Win10 VM QEMU/KVM clock not syncing

[Colin Law]

I have a Win10 VM running in QMU/KVM on Ubuntu. I routinely Save and
Restore the image and for some time all was well.  Recently, however,
I find that Windows does not resync the time when I restore the image,
and I think (but cannot be certain) that this started failing when I
upgraded to Ubuntu 20.04.  It is set to autosync in the windows
settings and resyncs fine when I tell it to sync.

Perhaps this is nothing to do with Ubuntu, in which case sorry for the
noise, but perhaps someone may have a suggestion.

Colin L.