[MP86950] Vout Losing Regulation At 0A Loading

Recently one of my project facing output losing voltage regulation at 0 Amps ( No Loading ).
Vin = 12V;
VDRV = 3.3V;
Vout = 0.6V / Iout Max. = 40A
*. Abnormal Condition:
The Vout will continue rising from 0.6V to 0.9V when Iout = 0A.

Please help it.
Best Regards
Jacky Chang