dan miller

The version is 0.15.4

Attached is a screenshot of the hopper with stuff stuck in it

I have this issue also and it is also repeatable.
Steps to reproduce:
1. create new world, any seed, creative or survival.
2. travel in the world in a straight line, any direction about 4096 chunks. (approx. 2, 1:16 scale maps)
3. watch your CPU usage pin to 100% as you travel.

So as you add more chunks to your game data. the more lag the game experiences.

Here is a better description to what I've seen.
Find a flat area and dig a one block hole.
Put a hopper into it.
Fill that hopper with cobblestone so it won't accept anything but cobblestone.
Drop a stack of dirt on the top of the hopper.
Place a water block nearby to create a water flow over the hopper.
I should see the dirt get washed downstream, but I don't.
If I do this same thing on the console version. the dirt always gets washed downstream.