I watched the video but it went by too fast for me and you made no commentary.
I see you set up a game and play an alt. You deliberately play badly and checkmate yourself in two moves. You keep switching back and forth between the two browser windows. You run the Game Review on one and it shows normally. On the second one, you seem to try out a number of variations.
What is the actual bug you are trying to point out?
Why do you have comments turned off? That is where people would include timelines, etc. to point things out.
https://youtu.be/U-559hZavMo
I can't figure out how to upload the screen recording, so I uploaded it to YouTube.