Wrong Quaternion angle with DMP at 500 DPS

I use the MPU9250 with DMP-code from MotionDriver 5.1.2 to compute 6-axe Quaternions.
With Gyro Full Scale Range of 2000 DPS it works.
But with Gyro FSR of 500 DPS, the heading angle moves a factor 4 too fast.
It seems to be exactly the factor between 2000 DPS and 500 DPS of the Gyro.

How can I solve that factor in the DMP?