openstack overcloud network provision failed after FFU : Cannot update physical_network in existing segment

Issue

After upgrading RHOSP from version 16.2 to 17.1 using Fast Forward Upgrade, and encountering an issue when regenerating the network Heat environment file for inclusion in the deployment command with the error "Cannot update physical_network in existing segment

(undercloud) [stack@director ~]$  openstack overcloud network provision \
--output /home/stack/templates/overcloud-networks-deployed.yaml \
/home/stack/templates/network_data.yaml
(...)
2024-12-20 16:24:46.278528 | 525400e2-94f4-cc7b-ddfc-00000000000e |       TASK | Create/Update composable networks
(...)
2024-12-20 16:24:49.936228 | 525400e2-94f4-cc7b-ddfc-00000000000e |      FATAL | Create/Update composable networks | localhost | item={'name': 'Tenant', 'vip': False, 'mtu': 9000, 'name_lower': 'tenant', 'subnets': {'tenant_subnet': {'ip_subnet': '172.16.0.0/24', 'allocation_pools': [{'start': '172.16.0.4', 'end': '172.16.0.250'}], 'vlan': 482}}} | error={"ansible_index_var": "idx", "ansible_loop_var": "item", "changed": false, "idx": 2, "item": {"mtu": 9000, "name": "Tenant", "name_lower": "tenant", "subnets": {"tenant_subnet": {"allocation_pools": [{"end": "172.16.0.4", "start": "172.16.0.250"}], "ip_subnet": "172.16.0.0/24", "vlan": 482}}, "vip": false}, "msg": "Cannot update physical_network in existing segment"}
(...)