Has anyone had issues with a throttle delay between the DX4R and the SR2000 rx?

For some reason I occasionally get about a half second delay between when I pull the throttle and when the car starts to move. Huge problem when starting a main.

ETA: I have the nizn batteries with voltage displayed between 6.6-7.2 during use. I also run a savox servo. There is no delay with steering or any 'glitching'. It just has a delayed trigger. tried it in two different vehicles.