Thank you!
The power of animation indeed. I noticed a darker patch in that area at one point, but thought nothing of it at the time. To be fair, this catch was pure luck! I was messing around with my mod scope at the time, but the adapter needed some more work. So I reattached it to the 50, and set it to capture in the background.
Exposure was 4ms, gain was around 20 at the time (haze came and went). I did one 500 frame run every minute. First frame: 12:55:13, last frame: 14:31:20 (11.55-13.31 [UTC] )
I posted it at SC today. I had to make a GIF that had an acceptable size first. I hate GIFs!
But since the video is broken in here, I will post it anyway