found the other place where ControllerNetwork is created
diff --git a/xos/synchronizers/openstack/model_policies/model_policy_Controller.py b/xos/synchronizers/openstack/model_policies/model_policy_Controller.py
index 2db7a63..c62b612 100644
--- a/xos/synchronizers/openstack/model_policies/model_policy_Controller.py
+++ b/xos/synchronizers/openstack/model_policies/model_policy_Controller.py
@@ -46,6 +46,8 @@
         if network not in ctrls_by_network or \
             controller not in ctrls_by_network[network]:
             controller_network = ControllerNetwork(controller=controller, network=network)
+            if network.subnet and network.subnet.strip():
+                controller_network.subnet = network.subnet.strip()
             controller_network.save()
     # relations for all images
     ctrls_by_image = defaultdict(list)