The area hopper minecarts will pick up items in is not centered.
A minecart with a hopper will pick up items that are up to a full block above it. However, some items will not get picked up. This is because the area is centered on the Southeast corner of the hopper minecart. Items that land in the red area in the picture below will get picked up. But, items that are outside the area, such as the brick in the picture below, do not get picked up. I was facing south when I took this screenshot. This does not happen with normal hoppers.
Environment
Windows7 and Java 7u11
Linked Issues
Created Issue:
The area hopper minecarts will pick up items in is not centered.
A minecart with a hopper will pick up items that are up to a full block above it. However, some items will not get picked up. This is because the area is centered on the Southeast corner of the hopper minecart. Items that land in the red area in the picture below will get picked up. But, items that are outside the area, such as the brick in the picture below, do not get picked up. I was facing south when I took this screenshot. This does not happen with normal hoppers.
Environment
Windows7 and Java 7u11
is duplicated by

Confirmed in 1.5.1.
Still an issue in 1.7.2. If this were fixed it would make a lot of automatic farms a lot better, at the moment hopper minecarts are a pain because of this.
Still an issue in 1.7.4.
This ticket has been marked as a duplicate of
MC-41881, in favor of the more general or better information provided.