The instances column, in the blocks management screen, links only to courses, but counts everything

I am not quite sure of what the bug is exactly, but under Modules->Blocks->Manage blocks, the "instances" shows a number, but when clicked, the list displays only courses and not the same number as the number displayed on the first screen.

It looks like it counts all instances, but the next screen only displays courses that have instances of the requested block type.