dripLava particles get stuck in ground

when playing around whit the particle command i noticed that the drip lava particels get stuck 2/16 of a block down in the blocks.

What i expected to happen was....:
The lava particles lay on top of the block after falling.
see https://www.youtube.com/watch?v=DSPam7TPE0Q

What actually happened was...:
they get stuck in the ground block about 2/16 of a block down.
see attached Pictures.

Steps to reproduce:
1. use Command /particle dripLava ~ ~1 ~ 1 1 1 0.001 1000 @a
2. wait for particles to land on ground.