I am certain that in previous versions "/particle smoke ~ ~ ~ 0 0 0 0.01 10" would display a few smoke particles EXACT to the players location/coordinates.

What seems to occur now is when a command like this is run, the particles display at the center of the block the player/entity is standing on resulting in a noticeable displacement of the particles away from the player/entity.

Steps to Reproduce:
1. Stand in the very corner or edge of a block (just make sure you are not near the center of a block)
2. Look straight up and go into a third-person perspective
3. Run a command such as "/particle smoke ~ ~ ~ 0 0 0 0.01 10"
4. Notice how the particles are not EXACT to the player, instead they are centered on the block you are standing on