Thanks for the reply!
I mean an HDA within another HDA, but where the first HDA is also embedded within the second HDA, like this: https://houdinitricks.com/embedding-houdini-digital-assets/
This makes it so that the definition for the embedded HDA doesn't exist outside of the “main” HDA. It is quite useful for being able to add “custom” HDAs to an already existing HDA, without having it clutter the Digital Assets list outside of where it is needed.
I'm sorry, I can't share the file I'm working on right now. But I could try to put together a test case
I have workaround where using a regular (non-embedded) HDA inside of my HDA works fine. It would just be preferable if I could use embedded HDAs.