Mp6532 gets into fault mode while slowing down by pwm

Hi,
I have a problem that when I slow down pwm from 30% to 5% or to 0% the driver gets into fault mode. I’ve noticed also the voltage on Rsense pulses down to -0.7V or less.
Pulling OCREF to VREG solving the issue but disabling over current features. Also lowering value of RSENSE improves the situation but also disabling the features.
Any advise how to solve it?

Regards
Krzysztof