I have an info obsidian farm, which I'm trying to set up to AFK. Unfortunately, I seem unable to guarantee every mined block is picked up by my hopper system. In the image below, I have a minecart hopper underneath the solid obsidian block, and hoppers completely surrounding the obsidian block. (even underneath the solid blocks).
Yet, you can see in the screen shot, they aren't grabbing that obsidian. This happens about 1 in 15 blocks that I mine.
Thoughts on how to set up hoppers to catch that errant obsidian?