What kind of battery are you using with it and how old is the battery ? Also what is the cut-off voltage on the ESC and can it be adjusted? Does this happen only at the full throttle ?
It might be that if you're using old low C lipo cells with high cut-off voltage, the cell voltage can go under high stress below that, even when fully charged. Secondly you might have selected the wrong battery type or cell count for the ESC (if they are selectable).