I have "One account per email address" set in my Firebase console and have implemented gmail and facebook authentication in my app.
In the scenario where a facebook account uses the same email as a gmail account here's what happens:
If I authenticate with gmail then later sign out and authenticate with facbeook (which uses the same email as the gmail), I'll get the error:
errorCodeEmailAlreadyInUse
However, if I authenticate with facebook first then authenticate with gmail, then no error is thrown and the user's entry in the Firebase authentication console gets overwritten.
What gives?