Embarrassing admission number 27:
I only have a previous-generation Roadster but it has the new 'pinch-tab' wiper attchment that BMW seems to use on all its newer cars, and so I presume including the F56. While fitting new blades, I knocked the lifted passenger wiper arm down onto the screen - and when it doesn't have a wiper fitted, the arm has two sharp points that contact the screen, one of which caused a little star crack. It can't be more than 5mm (3/16") diameter and or course is under the parked wiper, so I'm leaving it, but those with higher standards than me might like to watch out for this poor piece of design.