update IP address selection for v6

gso/workflows/iptrunk/create_iptrunk.py

@@ -410,7 +410,7 @@ def register_dns_records(subscription: IptrunkInactive) -> State:
             msg = f"Missing IP resources in trunk, cannot allocate DNS record for side {fqdn}!"
             raise ValueError(msg)
         ipv4_addr = subscription.iptrunk.iptrunk_ipv4_network[index]
-        ipv6_addr = subscription.iptrunk.iptrunk_ipv6_network[index]
+        ipv6_addr = subscription.iptrunk.iptrunk_ipv6_network[index + 1]
 
         infoblox.create_host_by_ip(fqdn, ipv4_addr, ipv6_addr, "TRUNK", str(subscription.subscription_id))
 

gso/workflows/iptrunk/migrate_iptrunk.py

@@ -548,7 +548,8 @@ def update_ipam(subscription: Iptrunk, replace_index: int, new_node: Router, new
     Move the DNS record pointing to the old side of the trunk, to the new side.
     """
     v4_addr = subscription.iptrunk.iptrunk_ipv4_network[replace_index]
-    v6_addr = subscription.iptrunk.iptrunk_ipv6_network[replace_index]
+    # IPv6 networks start with an unused address we need to skip past.
+    v6_addr = subscription.iptrunk.iptrunk_ipv6_network[replace_index + 1]
 
     #  Out with the old
     try: