SQLAlchemy "Exception during reset or similar" + "AttributeError: 'NoneType' object has no attribute 'pack'"

I'm getting an error when running this code:

engine = sa.create_engine([connection_str])
connection = engine.connect()

Full traceback:

Exception during reset or similar
Traceback (most recent call last):
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 682, in _finalize_fairy
    fairy._reset(pool)
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 887, in _reset
    pool._dialect.do_rollback(self)
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 667, in do_rollback
    dbapi_connection.rollback()
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/mysql/connector/connection.py", line 1236, in rollback
    self._execute_query("ROLLBACK")
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/mysql/connector/connection.py", line 1248, in _execute_query
    self.cmd_query(query)
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/mysql/connector/connection.py", line 828, in cmd_query
    packet.extend(lc_int(len(self._query_attrs)))
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/mysql/connector/utils.py", line 164, in lc_int
    return bytearray(struct.pack('<B', i))
AttributeError: 'NoneType' object has no attribute 'pack'
Exception closing connection <mysql.connector.connection.MySQLConnection object at 0x7fc69049fee0>
Traceback (most recent call last):
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 682, in _finalize_fairy
    fairy._reset(pool)
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 887, in _reset
    pool._dialect.do_rollback(self)
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 667, in do_rollback
    dbapi_connection.rollback()
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/mysql/connector/connection.py", line 1236, in rollback
    self._execute_query("ROLLBACK")
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/mysql/connector/connection.py", line 1248, in _execute_query
    self.cmd_query(query)
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/mysql/connector/connection.py", line 828, in cmd_query
    packet.extend(lc_int(len(self._query_attrs)))
  File "/Users/philipjoss/opt/miniconda3/envs/capra/lib/python3.9/site-packages/mysql/connector/utils.py", line 164, in lc_int
    return bytearray(struct.pack('<B', i))
AttributeError: 'NoneType' object has no attribute 'pack'

There is some more to the traceback but it's a During handling of the above exception, another exception occurred: and SO won't let me post any more code.

Queries etc work fine if I add a session but I always get this error at the end of the code running.

Python is 3.9.6, SQLAlchemy is 1.4.23, MySQL is 8.0.26.

Any ideas?

---

Update:

I've upgraded to SQLAlchemy 1.4.25 but still getting the error...

from SQLAlchemy "Exception during reset or similar" + "AttributeError: 'NoneType' object has no attribute 'pack'"