Authentication issue with postgres14 : InternalClientError: unexpected error while performing authentication: Incorrect padding

El informe señala asyncpg.connect y asyncpg/connect_utils.py, donde la autenticación falla con Incorrect padding al conectarse a Aurora PostgreSQL. Comienza investigando esa ruta de autenticación y si es posible reproducir el fallo intermitente; el issue no proporciona ninguna prueba del repositorio ni un reproductor fiable, por lo que no se han definido criterios de finalización.

• asyncpg version: 0.27.1
• PostgreSQL version: 14.6
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: No.
• Python version: python 3.8
• Platform: linux/x86-64
• Do you use pgbouncer?: No
• Did you install asyncpg with pip?: Yes
• If you built asyncpg locally, which version of Cython did you use?: No
• Can the issue be reproduced under both asyncio and
  uvloop?: No, we are unable to reproduce the issue consistently

We have run into an exception InternalClientError: unexpected error while performing authentication: Incorrect padding while trying to establish connection to Aurora PostgresSQL.

This issue is not happening consistently, as more often than not, request to DB goes through successfully, but scouring through the logs, we've found few instances in past as well.
We are using username/password authentication to connect to postgres instance.

Below is the error trace

 asyncpg.exceptions._base.InternalClientError: unexpected error while performing authentication: Incorrect padding
    return fut.result()
 File "/usr/local/lib/python3.8/site-packages/asyncpg/connection.py", line 2092, in connect
   return dialect.connect(*cargs, **cparams)
 File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
   dbapi_connection = rec.get_connection()
 File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
 File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 424, in checkout
File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 3166, in connect
 return super(Engine, self).connect()
 File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 747, in _connection_for_bind
     result = context.throw(*sys.exc_info())
     return await greenlet_spawn(
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/ext/asyncio/session.py", line 158, in scalar
   File "/app/./service_handler/api/deps.py", line 80, in get_account_or_404
     solved_result = await solve_dependencies(
    raise exc from None
     return await self.app(scope, receive, send)
     result = await app(self.scope, self.receive, self.send)
   File "/usr/local/lib/python3.8/site-packages/asyncpg/compat.py", line 56, in wait_for
     value = await result
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/_concurrency_py3k.py", line 115, in greenlet_spawn
     return current.driver.switch(awaitable)
    await_only(self.asyncpg.connect(*arg, **kw)),
    return self.dbapi.connect(*cargs, **cparams)
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 599, in __connect
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
    compat.raise_(
     compat.raise_(
     return fn()
     conn = bind.connect()
     return self._transaction._connection_for_bind(
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/ext/asyncio/session.py", line 139, in execute
     response = await func(request)
  File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 52, in app
     await self.app(scope, receive, sender)
     await self.app(scope, receive, send)
 asyncpg.exceptions._base.InternalClientError: unexpected error while performing authentication: Incorrect padding
     return await _connect_addr(
    await_only(self.asyncpg.connect(*arg, **kw)),
     raise exception
     compat.raise_(
     pool.logger.debug("Error on connect(): %s", e)
    self.__connect()
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 574, in get_connection
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 421, in checkout
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 424, in checkout
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 301, in connect
    conn = self._connection_for_bind(bind, close_with_result=True)
     result = context.throw(*sys.exc_info())
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/ext/asyncio/session.py", line 139, in execute
    account: Optional[models.Account] = await db.scalar(statement=get_account_stmt)
     solved_result = await solve_dependencies(
     await route.handle(scope, receive, send)
     raise exc from None
     return fut.result()
  File "/usr/local/lib/python3.8/asyncio/tasks.py", line 494, in wait_for
   File "/usr/local/lib/python3.8/site-packages/asyncpg/connect_utils.py", line 881, in _connect
     return await connect_utils._connect(
     value = await result
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/_concurrency_py3k.py", line 115, in greenlet_spawn
     connection = pool._invoke_creator(self)
     return fn()
     return self._wrap_pool_connect(self.pool.connect, _connection)
     return await greenlet_spawn(
   File "/app/./service_handler/crud/account.py", line 83, in lookup_account_by_company_id
   File "/app/./service_handler/api/deps.py", line 80, in get_account_or_404
   File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 580, in __call__
   File "/usr/local/lib/python3.8/site-packages/asyncpg/compat.py", line 56, in wait_for
     await compat.wait_for(connected, timeout=timeout)
     return current.driver.switch(awaitable)
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/default.py", line 584, in connect
     return dialect.connect(*cargs, **cparams)
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/create.py", line 578, in connect
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 599, in __connect
     raise exception
     compat.raise_(
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
     return super(Engine, self).connect()
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 1676, in execute
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/_concurrency_py3k.py", line 120, in greenlet_spawn
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/ext/asyncio/session.py", line 158, in scalar
     solved = await call(**sub_values)
   File "/usr/local/lib/python3.8/site-packages/fastapi/routing.py", line 204, in app
     await self.app(scope, receive, send)
     return await asyncio.wait_for(fut, timeout)
   File "/usr/local/lib/python3.8/site-packages/asyncpg/connect_utils.py", line 831, in __connect_addr
     return await __connect_addr(params, timeout, True, *args)
   File "/usr/local/lib/python3.8/site-packages/asyncpg/connection.py", line 2092, in connect
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/_concurrency_py3k.py", line 62, in await_only
     return self.dbapi.connect(*cargs, **cparams)
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 605, in __connect
     dbapi_connection = rec.get_connection()
     rec._checkin_failed(err, _fairy_was_created=False)
     return _ConnectionFairy._checkout(self)
     else engine.raw_connection()
     return self._transaction._connection_for_bind(
     result = await self.execute(
     result = await account.lookup_account_by_company_id(db=session, account_id=account_id, company_id=company_id)
   File "/usr/local/lib/python3.8/site-packages/fastapi/dependencies/utils.py", line 548, in solve_dependencies
     response = await func(request)
   File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 52, in app
   File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 241, in handle
   File "/usr/local/lib/python3.8/site-packages/starlette/exceptions.py", line 71, in __call__
   File "/usr/local/lib/python3.8/site-packages/asyncpg/connect_utils.py", line 773, in _connect_addr
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/dialects/postgresql/asyncpg.py", line 747, in connect
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
     fairy = _ConnectionRecord.checkout(pool)
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/pool/base.py", line 761, in _checkout
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 3212, in _wrap_pool_connect
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 3245, in raw_connection
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 96, in __init__
     return self._connection_cls(self, close_with_result=close_with_result)
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 3166, in connect
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/future/engine.py", line 419, in connect
     conn = bind.connect()
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 747, in _connection_for_bind
   File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 1526, in _connection_for_bind
     await self.app(scope, receive, sender)
     await self.app(scope, receive, send)
   File "/usr/local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 159, in __call__
 Traceback (most recent call last):
   File "/usr/local/lib/python3.8/site-packages/starlette/exceptions.py", line 82, in __call__
   File "/usr/local/lib/python3.8/site-packages/starlette/middleware/cors.py", line 78, in __call__
     await self.app(scope, receive, _send)