He says that it is glare, at tedious length. As of last year he thought it was the exhaust of another aircraft[1], plus he has stated his goal is to debunk UFO videos. He could have spent some of his tedious length and extensive reconstruction demonstrating the apparent position and velocity of that other plane, but he chose to spend it going on about what he should think is an inconsequential detail.
He says that it's glare produced by an object that the plane is tracking. He does not say that the entire phenomenon is glare; he says the opposite of that. The level of parsing you're doing here dwarfs whatever tone you picked up from the video itself.
Looking forward to his analysis of the angular velocity, which would be far more interesting. I'm sure it will be out soon since the model on his website should already contain it.
He says it is glare, yes, but he also references other IR camera footage to provide other examples of glare. And in each of the examples there is an object that is the source of the heat glare (e.g. a burning car).
I had also never heard of this incident before. My takeaway from the video: There's a camera glare artifact around an object; the motion of the object has to be understood while taking the camera gimbal system's actions into account. The next step would be to model the object's motion while doing so and checking if it's doing anything interesting.
I agree the video would be better if it made any effort to get into that. It's like Part I to a two-part story!
[ 1 https://www.theguardian.com/commentisfree/2021/jun/11/i-stud... ]