Systems don’t necessarily react based on the legal situation. A red light camera that’s improperly installed, poorly maintained, etc could essentially act randomly from a drivers perspective.
Which is why they are supposed to have a sworn officer review the camera footage. I have certainly had a camera flash me while waiting to turn right on red, still outside the intersection. They never sent me a ticket however since I had clearly not done anything illegal.
... which is why they are supposed to be regularly calibrated by an independent third party - with tickets automatically being void if law enforcement can't prove that it was functioning properly.