Not much else to be said, some way to help control boxes that take a weird bounce.
Perhaps a padded wall or netting that would deaden the momentum so boxes will drop onto a belt nicely.
#Placeable wall or netting to catch launched boxes.
pulsar pasture
craggy sequoia
I came to suggest a similar thing. The smaller boxes landing between two belts is especially annoying.
tardy perch
It’s not perfect, but right now I’m using decorations to do this. The small potted plants can fit on belts without interfering with boxes that are “locked in” to the belt system, but when the box is flying it’ll collide with the decoration’s hit box, and gives it more opportunity to get locked in to the belt. The tree also works like a bit of a backstop