Silly question (I’m renowned for silly questions), are you seeing the gimbal jerks in both the live video stream and the video off the SD Card?
The reason I ask, as you mentioned it was at a distance and not close in, could be due to signal quality. When at a distance and the signal is weaker the live video can stall, which would give the impression that things are not as fluid as expected. I won’t bore you with the details but there is a lot going on behind the scenes with the DJI link (compression, error correction, etc) and things can appear to slow down in adverse signal conditions.