How to keep the gripping force applied over multiple tasks

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I am planning a mission using smach for task planning. I want to grasp an object and keep the gripping force applied while moving the object. To grasp I am using the predefined action server of my hardware (Franka Emika Panda). Afterwards I am calling my own action servers to execute a predefined motion. However, when grasping the gripper only applies the specified force for a few seconds and then for the following task it only keeps the gripper fingers at the respective positions. This way the object is not grasped properly and rotates within the gripper. Any ideas how I can keep the force applied until I stop it with the respective "stop" action server? When I use the action server outside the smach environment it keeps the force applied as desired. Thank you for any help and suggestions!!