Easy-Pack tailgate does not unlock

For a few weeks now I have had the following problem with my tailgate: Sometimes it is not possible for me to open it automatically (key, handle or door). It does not unlock, but then wants to drive up correctly, what one hears from the noises and also sees at the beginning of a movement of the tailgate. Also the support with force does not change, since the lock is locked. After the vehicle was in rest mode (so overnight) the flap works perfectly. From there it is sometimes, not always, the end with Easy-Pack. Then it is called climbing, seat flaps and the mechanical unlocking effort. If you lock the lock with the open flap (manual changing of the hook) there is only a short noise when the Easy-Pack is triggered, the hook remains closed and can only be mechanically unlocked If the vehicle is in this condition, you can only hope that it will be released again after a long break. Does anyone have any idea what it might be about? Thank you very much