The shield item icon takes on the color of a non-existent banner in the inventory

The shield icon takes on the color of a non-existent or unapplied banner on the shield equipped or placed in a given slot.

For example, we created a green banner and applied it to a shield. Now, if it is swapped with a new shield without a banner applied, a banner will appear over the shield icon.

This is momentarily fixed after exiting and re-entering the world, however if you follow the steps again, the bug persists.