Contacted KUKA HQ and the issue was a similiar ''break fault'' on a another robot and is now solved via new Wov 6.0. They didnt want us to change some break parameters in the robot because it will change back to original values next time the robot gets connected to Wov. I dont know why but i guess our robot is a bit older now..?
But this problem happend only on when the signal Safe Operational Stop on X11 Contact pin 8 and 17 went LOW during T1 and EXT mode when robot is in motion or when drives and motors are Active without motion.. When signal is lost the robot breaks don't activate in time and the robot falls aprox 20mm Before the breakes come on. I solved this issue by jump wiring the signal and only using pin 4,13 & 19,29 instead… Works perfect!