Cabrioverdeck opens up in the morning in particular!

Hi, everybody! Cabrioverdeck opens (since spring) in turn (so 20x jerking), especially at my start of the day (even at midday, so not temperature-dependent!). Close is perfect! From the 2nd direct opening the function is perfect. If the vehicle stands several hours in the middle of the day, it just jerks 2 to 4 times, after 8 hours a little more. What can this be? Vehicle: Sebring Cabrio 2.7, year of construction: 2006. Thank you for your help!