Hi heat team.
 
I reported the following bug report [1] on Sep 2.
[1] https://storyboard.openstack.org/#!/story/2009164
Have you confirmed it?
 
This error seems to appear to have occurred after patch [2] was merged.
[2] https://review.opendev.org/c/openstack/heat/+/783971
 
Please kindly check it, thanks.
 
Regards,
Ayumu Ueha