Hopper placed below furnace attached to another hopper on the left and above a redstone lamp does not collect items output from the furnace.
Removing the redstone lamp resolves the issue.
Hopper placed below furnace attached to another hopper on the left and above a redstone lamp does not collect items output from the furnace.
Removing the redstone lamp resolves the issue.
Probably because of how the redstone lamp is powered. Powering it directly may result in it powering blocks, if possible try powering a block touching the lamp instead of the lamp itself.