Session is shared between two Flask apps on localhost
I had a similar problem, and I think the cause is that both instances would use the same "session cookie" in the browser.
The solution that fixed it for me was renaming the SESSION_COOKIE_NAME which is session by default.
app.config.update(SESSION_COOKIE_NAME=<new_session_name>)I found the solution via: https://stackoverflow.com/a/45497948/380038