ICM-20948 duty-cycle wrong result

Hello.
I first active the ACC in ICM-20948 in continuous mode with DLP BW 50HZ, data rate of 100. We get a good result. Then for save power we move to duty cycle with the some parameters. Now we got result lower significant. I don't find any remark or explanation about the duty cycle limitation or any reference take about calculation around the data rate and BW. I use the user guide of InvenSense ref DS-000189.
Bar.