It's a poor (not BMW) design because the slightest amount of wear, deflection or misalignment will cause the gear teeth to jump. Even worse, the amount of pressure to overcome the clutch to fold the mirrors manually is at the limit of what the mechanism can handle if everything is perfect and lubricated so is likely to damage the gears or break off one of the alignment pins. Like I said, the stops are mechanical and there will normally be power applied to the motor for a few seconds after the stop has been reached which is why you get the clicking from the gears if everything is not perfect.

__________________
1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)