docs(k8s): update warning

Author: bene2k1

pages/kubernetes/how-to/use-sfs-with-kubernetes.mdx

@@ -26,7 +26,8 @@ The Scaleway File Storage CSI driver supports the following features:
 - `ReadWriteMany` access mode: The volume can be mounted as read-write by many nodes.
 
 <Message type="important">
-  Ensure you have created your Kapsule cluster with the tag `scw-filestorage-csi` (or added it to an existing cluster) to have the File Storage CSI driver enabled on your cluster.
+  Ensure you have created your Kapsule cluster with the tag `scw-filestorage-csi` (or added it to an existing cluster) to have the File Storage CSI driver enabled on your cluster. 
+  Keep in mind, this tag must be specified at the **cluster level** rather than at the pool level. Setting it at the pool level has no effect.
 </Message>
 
 <Requirements />