I've noticed that on the CGO3+ as well...I suspect it is from autoexposure and/or auto white balance. Experiment with manual exposure and lock it to see if you get the same pulsation.
Has anyone experienced this? If RS is activated at any time during the flight, and then turned off, the TH becomes erratic and is reluctant to descend to a landing. If RS is never turned on, he TH behaves normally. Bizarre...