The bell part of bells worn on copper golems' "saddle" is not visible

Steps to reproduce

Execute the following command to summon a copper golem with a bell in its head slot.

/summon minecraft:copper_golem ~ ~ ~ {equipment:{saddle:{id:"minecraft:bell"}},NoAI:1b}

Observed behavior

The posts and bar of the bell will be visible, but the actual bell will not.

Expected behavior

All parts of the bell would be visible.