Chest not showing up in 3D Export

When exporting a preparing a 3d export with a chest or any other block entity, the structure block will show the block entities in the preview but wont export them.

 

Reproduce:

Create a model using a block entity (for example a chest)

Export the model with the structure block

Import into a gltf2 compatible modeling software

You'll see it

 

Expected:

The expected result is that the block entity will export.