flask-session replacing sqlalchemy DB address w/ localhost on google cloud

[BenTaub]

I have my session table in MySQL in SQLAlchemy in a database used by my application. Everything works when I run the application on my desktop but it fails when I run it in Google Cloud Run. I receive the following error message...
pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on 'localhost' ([Errno 20] Not a directory)")

This happens on this line of code...
Session(app=flask_app)

Prior to this failure, I connect to the same database and run a query against the session table using the same SQLAlchemy connection. More details about this problem are documented here.

1. Any ideas on why this might be happening?
2. I am using SQLAlchemy Core. Does flask-session require an ORM connection?

Thank you for your help,

Ben