verified unable to reproduce with latest 7.3ga :
now the instruction in the update guide are to
edit before the update /etc/heat/heat.conf on the undercloud:
rpc_response_timeout = 300 --> rpc_response_timeout = 600
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.