Sand falling next to lava source will display brief fire animation.

How to recreate
1) dig a 2x2x2 hole with the top open
2) place one lava bucket at one of the bottom corners
3) place unsupported sand at least 2 blocks above one of the corners that do not have the lava source
Observed result
right before the sand touches the ground it will display a brief fire animation

Expected result
the sand will touch the ground with no fire animation