DRV8323: Device failure during our customers build.

Tool/software:

I

I have designed your driver chip DRV8323H into a drive for a pump. In operation it rotates a brushless motor at constant speed and draws a supply current of 6A from a 28V dc supply.

It was shipped to a customer who intially recorded the same results as those that I had recorded. However when an end cover was placed over the drive it failed to work. Subsequent analysis of the problem discovered that there was a failure in the driver chip leading to damage of the package as shown in the attached photo. 

At first this was thought to be an assembly issue at our customers, however the same problem has occurred in a second drive.

Can you give any reason why this should be happening?