Electric mountain board VESC motors cutting out under load

Recently brought a Scramboard Vertigo Army Edition with dual VESC motor control. When the motors are put under load such as accelerating or hill climbing the power to the motors appears to cut in and out as if the VESC is unable to provide sufficient power. I was told the motors are 250KV with 10S power supply. Is it possible to make the power smooth without these cut outs?

You can hear the motors cutting out in this little video I took.
https://youtu.be/v_6zifEd_-k

The vesc calms down when the mosfets reach 80 degrees.

I don't know what to tell you.

Either you can improve the cooling, by adding a heatsink for example, there's a Lithuanian guy selling them cheap on ebay.

You could modify your riding style, to allow the vesc to stay cool.

You could purchase new esc, such as the newest vesc, or the Toro red brick.

Or you could analyze better the vesc logs to figure out why exactly it is not happy and then go back to step 1