TPS92662A-Q1: TPS92662 phase and PWM setting Cause current fluctuation

Part Number: TPS92662A-Q1


TPS92662 phase and PWM setting issues: 
During use, it is necessary to periodically set the phase and PWM registers(PWM Value is same). Testing has revealed that the current output by 92662 undergoes periodic jumps, as shown in the figure below, 
If the phase register is not set, this phenomenon will not occur, nor will it occur when the PWM is set to its maximum value.

What is the reason for the fluctuation in current generated by the phase and PWM registers? 
How to resolve this fluctuation?

Thanks!

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