Alright guys so I figured out what the issue was, it wasn't anything faulty or bad servo or any of that.

It's that my tekin rs pro gen 1 has a 6v 3a internal BEC, and I'm running a savox servo which is high voltage, brushless but it can be ran at 6v but savox servos are so power hungry that it's pulling to much current which is causing the brown out.

Solution, ether install an external BEC, castle creations has a 10amp for $20 and they can get expensive but that's more then enough. Or buy an ESC with a high voltage BEC like a tekin gen 2, or the tekin RSX!!