Bobbing sulfur cubes aren't affected by geysers

When sulfur cubes are placed on the top water of a potent sulfur geyser, they aren’t pushed up like other mobs.

Steps to reproduce:

1. Build a permanent sulfur geyser (bottom to top: lava, potent sulfur, 1-4 blocks of water) with preferably 2 or more blocks. Encase in blocks for ease of use.

2. Obtain a sulfur cube bucket with a block that makes them float, such as wood or wool.

3. Place the sulfur cube in the uppermost water block (this actually appears to affect any water block, but the sulfur cube will float to the top slowly)

Expected result:

The sulfur cube will blast upwards rapidly, even when placed in water, as seen in all entities including sulfur cubes with sinking blocks.

Actual result:

Floating sulfur cubes just float at the surface, unaffected by the geyser. They work as normal if placed in the air part of the geyser.