Comparator does not detect items travelling through the hopper depending on their setup. How the hoppers are facing DOES affect whether any items are detected or not.
Steps to Reproduce:
Build the setup in
and
Drop a stack of items at the top of the hoppers
Observed Results:
In the setup with all the hoppers pointing to the side, none of the items are detected by the comparator. However, in the setup with hoppers pointing downwards into each other, the items are detected by the comparator.
Expected Results:
The comparator detects items travelling from both setups and not when they are only facing down.
This is just a side-affect off how hoppers work. The first hopper pushes the item into the second one, but at the same time the third one pulls said item into the second one. There is never technically an item in the second hopper to detect.