[Firestore] Six unintentional documents written to database

[maxmoros]

Describe the bug
Six unintentional documents have been written to new collections. Upon making a document write request, these six additional documents are attempted:
_createTime
_fieldsProto
_readTime
_ref
_serializer
_updateTime

These documents trigger my cloud function and throw errors. However, the documents do not appear in my cloud firestore database. This leads me to believe that cloud_firestore is sending a broken request and firestore removes these documents immediately after triggering the cloud function.

These names do not exist in my code, but do exist in the document.js code.
https://googleapis.dev/nodejs/firestore/latest/document.js.html

To Reproduce
Write a document to a new collection that has a cloud function console logging the document id.
Try this until these six hidden document write attempts appear.

Expected behavior
I do not expect these documents to be written. I expect only the single document I request to be written to the database.

Additional context
https://stackoverflow.com/questions/62702756/firebase-cloud-function-triggers-six-hidden-xxxxx-documents-in-new-collecti?noredirect=1#comment110886763_62702756

Flutter doctor
Run flutter doctor and paste the output below:
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, 1.19.0-4.2.pre, on Mac OS X 10.15.5 19F2096, locale en-CA)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 11.5)
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.0)
[✓] VS Code (version 1.46.1)
[✓] Connected device (3 available)

• No issues found!

[maxmoros]

Ignore the Flutter Beta channel, I just switched that today to play with flutter web. My app is posted with the latest stable flutter version

[TahaTesser]

Hi @maxmoros
Can you please provide a complete reproducible minimal code sample
Thank you

[Salakar]

Hey this has been fixed as part of #2582 / #2913 - pending release.