It could be one of many possibilities, including an invalid switch state, a hydraulic bypass valve open, low hydraulic fluid due to a leak. It looks like it continues to maintain pressure if a fault occurs in a suspended state, to prevent the top from drifting and causing damage. Make sure there is not anything in the trunk interfering with the top stowage area. It more than likely has fault codes stored that would relate to the fault. It would need a scan tool to access those.