I know it is not strictly related, but your video export was ridiculously huge. Don't let Blue Iris re-encode the video during export.
I notice the timestamp in the corner of the video is jumping back and forth when the glitches appear. I am going to guess that Smart Codec was on, and turning it off may solve the problem. If not that, then I really have no idea.
Good catch. Just changed that, also. Funny when I set all of that up using Amcrest IP Cam config, it didn't take, I guess. I no longer use that app anyway.