Can't launch instance if name ends with a number

Issue

• instance fails to launch if name ends with a number

exception_handler_v20\n    request_ids=request_ids)\n', "neutronclient.common.exceptions.BadRequest: Invalid input for dns_name. Reason: '1mt-rhel-8.4.0-20201125.n.0' not a valid PQDN or FQDN. Reason: TLD '0' must not be all numeric.\nNeutron server returns request_ids: ['req-ccaf2bcd-e831-4dca-bfb8-601e3ae402e8']\n", '\nDuring handling of the above exception, another exception occurred:\n\n', 'Traceback (most recent call last):\n', '  File "/usr/lib/python3.6/site-packages/nova/compute/manager.py", line 2161, in _do_build_and_run_instance\n    filter_properties, request_spec)\n', '  File "/usr/lib/python3.6/site-packages/nova/compute/manager.py", line 2537, in _build_and_run_instance\n    instance_uuid=instance.uuid, reason=six.text_type(e))\n', "nova.exception.RescheduledException: Build of instance e7d11ace-869f-4222-892a-6036770a49e3 was re-scheduled: Invalid input for dns_name. Reason: '1mt-rhel-8.4.0-20201125.n.0' not a valid PQDN or FQDN. Reason: TLD '0' must not be all numeric.\nNeutron server returns request_ids: ['req-ccaf2bcd-e831-4dca-bfb8-601e3ae402e8']\n"]