When doing /setblock in the air with coral/coral fan/kelp/kelp plant/conduit it causes the water it is summoned with to flow which is inconsistent with how seagrass, tall seagrass & sea pickle are summoned.
- Do /setblock ~ ~ ~ brain_coral in the air
Notice the water flows
- do /setblock ~ ~ ~ seagrass in the air
Notice the water doesn't flow