According to rule R8g (emphasis mine):
I assume that all previously-legal lights, including the VEX Flashlight, are still legal as long as they aren’t used in a way that could confuse the Vision Sensor, but I wanted to mention this rule in case anyone else might get confused by it.
If anyone thinks this would be a good question for the Q&A, feel free to ask about it there. (Just make sure there aren’t any double posts.)
P.S. I’m not part of a registered team, so I can’t ask the question myself.
Edit: When I first posted this, I accidentally put it in the In the Zone channel.