LT3972 failure

To whom it may concern,

   LT3972 switching regulator is widely used at some of my designs on RF equipement as main input regulator.

  We have experienced diferent problems with mentioned device and its related LT3971.

In some ocasions regulator fails and sets its output at the same value of its input voltage (+24V) therefore circuitry supplied is widely damaged. 

In some other intetgrations regulator does not works properly due to a, what we think, poor conexion to ground through the bottom pad. In these cases we are forced to resolder manually. 

Both cases are being repeated in time, at a low ratio, but repeated... and are looking for some advice to avoid any occurrence of these issues.

You will surely need further information regarding PCB design and auxiliary circuitry used, etc to provide some support... 

I'm really lookig forward to receiving your feedback.

thanks in advance.