Custom Item paths to images not working

[nearnshaw]

If I define a custom item that includes images as part of its assets, the path to these doesn't get properly referenced.

This is blocking the creation of certain smart items like scrolls. It's also affecting the quality of the image smart item that's already available.

For example, in this text scroll smart item, a show text action also shows a background image.

text_scroll.zip

In the composite.json, I see the path to the image is the following, which looks consistent with how the gltf path is referenced
{assetPath}/scroll_fantasy_dark.png

But when I add the entity to one of my scenes, the item fails to show the image. If I open up the advanced mode for the item, I see this:

At this point the path should have been updated to replace the string {assetPath}
custom/magic_scroll/scroll_fantasy_dark.png

The same happens if the image is on the Texture field of the Material component.

image.zip