hoppers weird with a wooden pressure plate on top

Put the summary of the bug you're having here
items thrown/dropped on wooden pressure plate, which was on a hopper, caused the items to bounce

What I expected to happen was...:
Either:
1. items to be sucked up before landing on pressure plate, or
2. items land on pressure plate and disable hopper

What actually happened was...:
items bounced on the pressure plate. i am unsure as to whether or not hopper was "disabled" from the pressure plate.

Steps to Reproduce:
1. place down a hopper
2. right click while sneaking to place a pressure plate on top
3. throw/drop an item/items on top of pressure plate