DRV3946-Q1: current ripple is too large

Tool/software:

Hi team,

Customer have two DRV3946-Q1 to drive 4 relay coils(PC is 400mA, HC is 240mA,  PWM Frequency Settings is 2k ), and they only control 1 channel to drive coil, the current ripple waveform and OUT waveform is normal as below:

But when they open 2 or 4 channels at same time, current ripple will be larger at any channel, seems different channel are interfering with each other, as you can see the abnormal PWM waveform:

first DRV3946's OUT2 and second DRV3946's OUT2 have been controlled:

All the 4 channels are turned on:

Not sure how we can deal with that? I doubt there is something wrong in PCB layout leading to interference.

Schematic and layout will be attached for your reference.

BR

Amber