Update IPtrunk migration IPAM step behaviour

gso/workflows/iptrunk/create_iptrunk.py

@@ -409,7 +409,7 @@ 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))