I am using the v9 Web SDK.

I have a collection called 'transactions-in' which keeps a record of every transaction into a cardano wallet.

From time to time my server will send a transaction in response to each transaction in this collection (such as sending an nft or refunding ADA) and I want to add these transactions into a subcollection on the relevant transaction document, so the structure looks like this:

• collection: 'payments_in'
• document: document ID
• subcollection: 'related_transactions'
• document: newly created document reference

This is the code I have to get the right path to the newly created document ref and upload some test data into the firebase emulator:

  //1. Get current doc
  const currentDoc = doc(db, 'payments_in', transactionId);

  //2. Build refund database entry
  //2A. Get collection from database (will create one if doesn't exist)
  const newCollection = collection(currentDoc, 'related_transactions');

  //2B. Get a new document from database within new collection
  const newSubDoc = doc(newCollection);

  //2C. Upload entry to database
  await setDoc(newSubDoc, { test: 'test' });

When I log the path of newSubDoc I get this, so the path looks good (I think??): payments_in/kXK5pimm29nRhU4CohA6/related_transactions/NL11eYmsB4M9vHw6PI8X

However when I try to submit the entry using setDoc I get the following error message:

@firebase/firestore: Firestore (9.1.1): Connection GRPC stream error. 
Code: 3 Message: 3 INVALID_ARGUMENT: Document name "projects//databases/(default)/documents/payments_in/kXK5pimm29nRhU4CohA6/related_transactions/tLoCiHUJaA2uYhxt7drb" 
lacks a project id at index 9.

Does anyone see what I am doing wrong here?

Thanks