I noticed that some of my belts are stuttering a bit, which I found a bit strange. When I followed them back, I noticed that a notch input with a belt launcher immediately after it seems to be deleting every 4th or 5th shape that passes over it.
#Random pieces vanishing
languid dagger
This is the second layer of my 12x12 stacker. With the top layer off, it's a bit hard to tell, but you can see them disappearing right before the first jump sometimes. If you look at the second jump right in the middle of the image, you can tell that the two jumps next to each other keep getting out of sync because of a missing shape