Invisible spawn eggs and copper golem statues in old superflat worlds

After updating to Minecraft Bedrock Edition 1.21.130, several newly added items become invisible in older superflat worlds.
The items appear correctly in other world types, and they work normally when placed, but their icons and models do not render.

The following items are invisible in the inventory of old superflat worlds:

• Nautilus Spawn Egg

• Copper Golem Spawn Egg

• Camel Huks Spawn Egg

• Parched Spawn Egg

• Zombie Nautilus Spawn Egg

• Copper Golem statues

When placing them in the world, the entities exist and function, but their models remain invisible.
Example: A Camel can be mounted and moved, but the Camel itself cannot be seen.

This issue does not happen in:

• New superflat worlds

• Normal old worlds

• Normal new worlds

So far, it only affects my older superflat worlds created before recent updates.

These superflat worlds were created several years ago, and I still use them regularly. They have been carried over through multiple updates.

No mods, shaders or non-default resource packs are installed. Only the default Minecraft packs are active.

Expected behaviour:
All spawn eggs and new entities/statues should be visible in the inventory and world, including in old superflat worlds.

Observed behaviour:
Spawn eggs and statues appear invisible in the inventory and remain invisible when placed in old superflat worlds, even though their interactions still work.

I don’t know if in works but these are some steps to reproduce:

1. Open an older superflat world created in a previous version of Minecraft Bedrock.

2. Obtain one of the affected spawn eggs or copper golem statues.

3. Observe that the item icon is invisible in the inventory.

4. Place the entity/statue.

5. Observe that the placed entity/statue is also invisible, though it functions normally.