Flipsky 4.12 suddenly/randomly brakes

Hello,

Ive a big problem with my Flipsky 4.12 50A VESC...when driving for a few minutes it suddenly starts to brake randomly for 1-2 sec then switches back to normal and repeats after a short time again and again.

This is very dangerous...I almost fell from my board because of this.

My Motor setup:

BLDC / Motor Current Max and Max Brake: 50A / absolute max current: 120A

Battery current max: 50A / Battery current max regen:  -20A

I use a 190kv 90A Brushless outrunner motor:  https://hobbyking.com/de_de/kd-53-30-high-voltage-brushless-outrunner-190kv.html

6s 5000mah Battery

Flipsky 4.12 50A VESC

Plz HELP!