BUG #16407: Column mismatch

The following bug has been logged on the website:

Bug reference:      16407
Logged by:          onlinejudge95
Email address:      onlinejudge95@gmail.com
PostgreSQL version: 12.2
Operating system:   Docker
Description:

I have a flask app that connects to a Postgres DB and stores the user info
there.
For local development purposes, I am using docker to bring up 2 containers
one my app and the other of Postgres.
In my models, I am defining my primary key as a column named id

class User(db.Model):
    __tablename__ = "users"
    _id = db.Column(UUID(as_uuid=True), primary_key=True, unique=True,
nullable=False,)
    username = db.Column(db.String(128), nullable=False)
    email = db.Column(db.String(128), nullable=False)

    def __init__(self, username, email):
        self._id = uuid.uuid4().hex
        self.username = username
        self.email = email

Everything works fine in my local system when I use this Dockerfile

FROM postgres:12.2

LABEL maintainer="onlinejudge95"

COPY configs/db.sql /docker-entrypoint-initdb.d/

But while deploying to Heroku and using the Postgre image there, I receive
the following errors on any operation that queries my DB.

sqlalchemy.exc.ProgrammingError: (psycopg2.errors.UndefinedColumn) column
users.id does not exist

So I decided to change my models to use _id instead of id, this change seems
to work fine.
Is this a known discrepancy?