The bug

If, via commands, one item that renders as an entity has an item model specified that should have it render as a different entity, it will not render as the entity specified for the item model component, instead rendering the one associated with the base item's ID.

How to reproduce

1. /give @s chest[item_model="minecraft:stone"]

2. /give @s shulker_box[item_model="minecraft:stone"]

3. /give @s chest[item_model="minecraft:shulker_box"]

4. /give @s shulker_box[item_model="minecraft:chest"]

Expected results

In order we'd get: a chest whose item form looks like stone, a shulker box whose item form looks like stone, a chest whose item form looks like a shulker box, and a shulker box whose item form looks like a chest.

Actual results

The first two are as expected. However, for the last two, the chest still looks like a chest and the shulker box still looks like a shulker box.