Particles spawned by brushes in the left hand move in the wrong direction

In a typical scenario, where a brush is placed in a player's right hand, the brush will initially move right-to-left and particles will be spread to the player's left. As such, the particle motion is consistent with the brush motion.

However, this consistency can be broken by moving the brush to the left hand. This can be done by changing the main hand to the left hand, or by placing the brush in the off hand. Once this is done, the brush will initially move left-to-right, but particles will still spread to the player's left.