An anvil has te same hight as a normal (solid) block. Yet when you stand on top of an anvil you clearly stand a small distance lower then when you would stand on top of a normal block. This is very noticeable when you walk back and forth over a normal block and an anvil.
Is this still a concern in the current Minecraft version 1.6.4 / Launcher version 1.2.5 ? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.