Wilhelm,
Cracks such you describe are not uncommon.
I'm only guessing here, but do you/anyone else who drives the car/ any passengers ever hold on to the windscreen when you get into or out of the car?
This can often result in stress or flexing which then weakens the screen and can cause cracking.
As I say, it is purely a 'shot in the dark,' but it is a common cause of cracking
Putting the hood up in such a way that the tension is not evenly distributed can have the same result ( although less so with your car than the old, multi stud type of hoods)
best wishes,
G
