Hi @F Ahmed ,
>however cluster ( SQLAGCLuster) doesn't update the ip unless I restart the cluster.
SQLAG cluster IP? Did you mean SQL AG listener IP, could you describe this issue more clearly or share us a screenshot to better understand this issue?
IP address for SQL server AG listener changed to another subnet IP when you failover the AG to another subnet. You need to assign two different virtual IPs (one from each subnet) to your AG listener. When the Availability Group Listener (AGL) is configured properly, it will have an IP address for each defined subnet and have an “OR” dependency on each of the IP addresses.
Please check your steps follow below blog to find if you missed something.
Configure SQL Server AlwaysOn Availability Group on a Multi-Subnet Cluster
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