Hi Pumpkin,
There is not a simple answer to this… There are still many things about the DMP that we do not understand. You are also not the only person to notice this. There is useful background information in the open and closed issues in the ICM-20948 GitHub repo:
https://github.com/sparkfun/SparkFun_IC … is%3Aissue
https://github.com/sparkfun/SparkFun_IC … s%3Aclosed
It may indeed be a scaling issue. If you want to try some experiments, please try Example10_DMP_FastMultipleSensors. You can edit the code to change the rate and scaling:
https://github.com/sparkfun/SparkFun_IC … #L370-L379
https://github.com/sparkfun/SparkFun_IC … #L400-L407
https://github.com/sparkfun/SparkFun_IC … #L459-L475
If you work out the answer to this, please tell us!
Good luck!
Paul