The issue is still being discussed among us.
In the meantime, here’s a couple of my leads: 
- Before performing the request against the database, are you casting the IDtoObjectId?
- The call between the frontend and the backend targets /forest/Source? Is that correct? Shouldn’t it be/forest/sources?
You might want to take a look at this thread. 
Also, what’s the intent with this project architecture? Or what is the use case you are trying to do?
EDIT: One of our team will organize a live debug session with you, stay tuned 

