Having an item laser relay attached to a chest and a hopper next to the relay (keep in mind that the relay's base is touching the chest, not the hopper) will cause the relay to prefer the hopper instead of the chest.

Same thing happens for vanilla chests. I have used the crystal chest only to visually demonstrate where the items end up. Additionally, this thing only seems to happen when the relay is upside down. Putting it above the chest, prefers the chest instead of the hopper.

Working as intended.