What I expected to happen was...:
I have a hopper under another hopper with a comparator checking if item passes

What actually happened was...:
When the item passes, it moves too fast for the item to be detected, BUT, if the hopper is facing side ways into another container it works fine as usuall

Steps to Reproduce:
1. Place hopper on top of another hopper with comparator checking top hopper
2. Throw item into top hopper