Hi Boris,
I think this is related to a regression in the python-yaql package.
The same issue we hit upstream here:
https://bugs.launchpad.net/tripleo/+bug/1750032
You can work around the issue by downgrading the python-yaql package
to the previous version. Or apply this fix to t-h-t:
https://review.openstack.org/#/c/545498/
Hope this helps,
Dan