BostonJon

This is how mine operates also. I was a bit surprised that the "thing" goes back to the top again after closing the cover because then when the hatch opens, the cover snaps up very quickly instead of rolling up slowly.

There is a small magnet on the very end of the part of the cover that goes into the channel. This magnet activates a sensor behind the trim, which tells the car if the cover is in the up or down position. That is why you don't hear the actuators "click" to release the cover if it is not engaged into the track. Perhaps your magnet is not properly aligned with the reed sensor or the sensor is faulty.

Also possible is that your actuators are releasing, but not actually physically moving out of the way of the ends of the roller cover.

The whole cover mechanism is a great idea, but seems poorly designed in my opinion. I had mine completely apart because the motor was seized. Thankfully I was able to get it working again because the components are extremely expensive.

White_Spot™

I have to find a way to verify if this sensor / magnet are working correctly.

No, I confirm that the actuators moves and release the cover, but the covers stay in place and do not move.
Apparently nothing is holding the covers so why I said maybe the "thing" that move the cover down are not going up and holding the cover in that place.

White_Spot™

So the other day I decided to look a little bit a this and it seems that the roller cover stand still with nothing holding it.
I put a little bit of vaseline to lubricate the zone of the actuators and the rod of the roller cover and nothing as changed.

It seems to me that the roller cover is not being "pushed" (roll in) sufficiently by its "spring" and because of that it stand in that place when the actuators retracts.
Sometimes I retract the actuators by hand and move the roller cover up a little bit to pass the actuators zone, and the roller cover do not go up immediately, I need to jiggle it a little and only after that the roller cover go up alone.

There is anyway to "reinforce" (or something else) the spring of the roller cover?