thanks for the advise. I found where to switch between "functional" and "timing" simulation. I attached two pictures one for each mode.
As expected the functional simulation shows (luckily for me) that the code works correctly, but the timing simulation shows unexpected behaviour.
So back to the roots, is there any explanation why the 1ns spike appears at 70ns in the timing simulation? I understand that the different length to the output pins cause the different timestamps where the pins change there value but the spike? I dont have any idea how to avoid this.
I will try to analyse the code in reality (scope).
But unfortunally I found unwanted strange behaviour in the hardware implementation and traveled down to the code and simulation - and (surpise) it's unclear there aswell.
Maybe the volcano ash from Iceland had more impact than we all recogniced :-)