This is a tracking bug for reverting https://review.openstack.org/#/c/463577/1 once the problem (probably in Heat, or possibly something in t-h-t) is fixed. Context follows:
There was a Heat bug that conditional resources didn't work well in depends_on:
https://bugs.launchpad.net/heat/+bug/1649900
This bug has been fixed, but we're still hitting it in TripleO:
https://bugs.launchpad.net/tripleo/+bug/1689553
The problem is fixed by removing the conditions:
https://review.openstack.org/#/c/463577/1
... so it's likely that this issue is still somehow present, perhaps in a way that is only triggered by the TripleO templates but not the test cases that were used to verify the fix of the original Heat bug.
This happened in an upgrade job from Ocata to Pike, but only the overcloud is being upgraded there. Undercloud was Pike all the time (openstack-heat-common-9.0.0-0.20170505082259.b3d3ad0.el7.centos.noarch).
I think we can close this as won't fix