It might need lubrication, and it can be adjusted.
My top was slow, and did not go to completely closed position.
I started off by lubricating it with some grease. I used some stuff I had around, but others will tell you that lithium grease is best, and it probably is, but I just did with what I had.
I went to the trunk, and there is a place to make adjustments to the sunroof behind the left hand side trunk panel.
I messed with mine until I got it in the right position.
A lot of Trial and error on my part until it was right.
I remember pulling a white knob out like a clock adjustment pin. and then turning a nut like thing that was plastic with a ratchet. once I had it adjusted right, it was all good. I did have to use the open and close button a few times as well to get everything organized.
But I am not a tech, and I take no responsibility for this if I am wrong.
You will want to wait on a tech to answer.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.