Water and lava do not render on copper golems' heads if summoned as such

If a copper golem is summoned with a powder snow bucket on its head, it will appear with a powder snow block on top. However, if a copper golem is summoned with a water bucket or lava bucket on its head, it will not have a water or lava block displayed on top of it, which is obviously inconsistent and incorrect, as in all three cases the item in question is the one that places the block.

Commands to reproduce:

/summon minecraft:copper_golem ~ ~ ~ {equipment:{head:{id:"minecraft:water_bucket"}},NoAI:1b}
/summon minecraft:copper_golem ~ ~ ~ {equipment:{head:{id:"minecraft:lava_bucket"}},NoAI:1b}
/summon minecraft:copper_golem ~ ~ ~ {equipment:{head:{id:"minecraft:powder_snow_bucket"}},NoAI:1b}

To fix, either have them render the fluid block as expected, or make copper golems render item models instead of block models, such that the bucket is instead displayed.