fix cassettes + apply review comments

Author: Mia-Cross

internal/services/rdb/instance.go

@@ -667,6 +667,10 @@ func ResourceRdbInstanceRead(ctx context.Context, d *schema.ResourceData, m inte
 		_ = d.Set("private_network", pnI)
 
 		for _, endpoint := range res.Endpoints {
+			if endpoint.PrivateNetwork == nil {
+				continue
+			}
+
 			if endpoint.PrivateNetwork.ProvisioningMode == rdb.EndpointPrivateNetworkDetailsProvisioningModeIpam {
 				resourceType := ipamAPI.ResourceTypeRdbInstance
 				opts := &ipam.GetResourcePrivateIPsOptions{
@@ -675,10 +679,12 @@ func ResourceRdbInstanceRead(ctx context.Context, d *schema.ResourceData, m inte
 					PrivateNetworkID: &res.Endpoints[0].PrivateNetwork.PrivateNetworkID,
 				}
 
-				privateIPs, err = ipam.GetResourcePrivateIPs(ctx, m, region, opts)
+				endpointPrivateIPs, err := ipam.GetResourcePrivateIPs(ctx, m, region, opts)
 				if err != nil {
 					return diag.FromErr(err)
 				}
+
+				privateIPs = append(privateIPs, endpointPrivateIPs...)
 			}
 		}
 	}