1 Open VRChat
2 Open your camera
3 Set pin 1
4 Set pin 2 to a different position (use flying to zoom out, etc)
5 Switch pin
6 Screen will flash
This is visible on streams and recordings, and could be an accessibility issue if someone's switching streams quickly. It also just doesn't look great, and is jarring.
My theory is that it's seeing the blue camera ghost for a couple of frames, but I can't say for sure.