Smoke is passing through block, that is right above source of smoke

When you have, for example, torch right under ceiling and go on floor right above it, you can see smoke going out of the floor, which is really annoying.

What I expected to happen was...:
Smoke should get stopped by solid block, that is above him.

What actually happened was...:
Smoke is going through block that is right above him, like if there was clear space and you can even see him coming from upper side of that block.