diff --git a/internal/pkg/onuadaptercore/omci_vlan_config.go b/internal/pkg/onuadaptercore/omci_vlan_config.go
index 038b756..3201150 100644
--- a/internal/pkg/onuadaptercore/omci_vlan_config.go
+++ b/internal/pkg/onuadaptercore/omci_vlan_config.go
@@ -501,8 +501,8 @@
 								"device-id": oFsm.deviceID, "cookie": delayedCookie})
 							return fmt.Errorf(" UniVlanConfigFsm suspended add-cookie-to-rule aborted %s", oFsm.deviceID)
 						}
-						oFsm.mutexFlowParams.Lock()
 						flowCookieModify, requestAppendRule = oFsm.reviseFlowConstellation(ctx, delayedCookie, loRuleParams)
+						oFsm.mutexFlowParams.Lock()
 					} else {
 						logger.Debugw(ctx, "UniVlanConfigFsm flow setting -adding new cookie", log.Fields{
 							"device-id": oFsm.deviceID, "cookie": newCookie})