robotguy :
In this video there's a small glitch when the concrete breaks at 1:38. What is the name of this effect, and why does it happen? How to prevent it?
https
/www.youtube.com/watch?v=cfVvzjVzeE0
If you mean the flash in the lower half of the screen about three seconds later than the time you said, that's called a flash, and the ONLY way to prevent that is to put a piece of tape over each and every camera that comes into that area. If you make the entire place much brighter though (half dozen 1kW lamps lighting the whole room), it might stop most cameras from using their flash.