DRV8432 unused output port shorted to PVDD internally

Hi,

I am currently applying DRV8432 to drive a 3 phase BLDC motor. Thus I am only using half bridge A, B and C and left half bridge D floating at the output.

But recently I found a damage board where PVDD (+48V) and GVDD (+12V) are both shorted to ground (PVDD to ground: 6ohm & GVDD to ground: 8ohm).

After checking, I found out that the shorted was actually originated from DRV8432 output port D.

Output port D is directly shorted to PVDD with almost 0ohm, around 8ohm to ground, and around 2ohm to GVDD.

However, I am not using Output port D to drive any load in my application.

Can you advice what might have cause this kind of damage to port D?

I have set overcurrent protection in latching mode at 5.8A and it never trigger any overcurrent protection before port D is damage.

Looking forward for your reply. Thank you.