"... missing FROM-clause entry for table..." error on simple SQLAlchemy join query?

Question

Let's say I have a simple model:

class Entry(db.Model):
    __tablename__ = "entries"
    id = db.Column(db.BigInteger(), primary_key=True)
    event_id = db.Column(db.BigInteger())
    entry = db.Column(db.String(64), nullable=False)

... and I run a query like this:

from models import Entry
from sqlalchemy.orm import aliased
Comment = aliased(Entry)

answers = Entry.query.join(Comment, Comment.event_id==Entry.event_id) \
.with_entities(
    Entry.event_id.label("entry_event_id"),
    Comment.event_id.label("comment_event_id"),
    Comment.entry.label("comment"),
    Entry.entry.label("answer")
) \
.all()

This feels pretty straightforward, but I'm getting:

sqlalchemy.exc.ProgrammingError: (psycopg2.errors.UndefinedTable) missing FROM-clause entry for table "entries_2"

entries_2 here is just the aliased table. Does anyone have an idea of what's going wrong?