DRV8316C: IC failure with burn mark

Tool/software:

Hello, 

We are using DRV8316C in our system, and have received a unit returned due to a motor not spinning. 

Upon investigation , we found out that the DRV8316C IC has failed with a burn mark. Refer to the image below. 

After cleaning the burnt mark, we can clearly see that the failure occurred across pin 9 - 11, which are all VM pins. 

There was no short between GND with these pins (VM is shared with other motors in our system, and those are operating fine) . 

My question for the TI team is : 

1. Based on the burnt pins and burn mark on the IC , does TI team have guess on what might have caused this failure? 

2. Has the TI team seen same failure mode before? 

Sincerely, 

Tsugumi