The vacuum hopper seems to take up a full block, so you can't access the inventory next to it if you're on the opposite side. It should be adjusted to match it's rendering size!

This is not really a bug as such - it's to make it easier for us to detect items hitting the hopper.

Personally I'd say - although annoying, it's working as designed. Possibly someone might change it at some point, but this issue is a month old so closing for now.