External BEC needed for RX8 high voltage/Mech brakes?

[Aceldama]

I'm having a strange issue with my truggy setup at the moment maybe someone could help diagnose:

I'm running 6s lipo and mechanical brakes.

Under hard braking it seems that the steering servo takes a second to 'recover' as if it's not getting enough voltage. I can steer excellent off throttle/brakes. But if I"m using brakes/throttle (mostly brakes) during steering, or try to steer immediately after I don't get the full range.

Anyone else seeing this problem that has a similar setup to mine? This behavior is easily observed on a high grip surface like a parking lot. My turning radius is easily double for a second or two after hard braking.