Relates to MC-277648.

The bug

If an item which is not a map is assigned the minecraft:filled_map model using the component system, it will not be held like a map in first person view.

How to reproduce

1. /give @s blue_wool[minecraft:item_model="minecraft:filled_map"]

2. Get an empty map and right click with it to obtain a real map

Expected results

The blue wool would be held like a map in first person. It wouldn't render any map data due to none being present, but it would render the blank map texture.

Actual results

It's held like any other 2D item.