Task got Future attached to a different loop after upgrading python

[mdczaplicki]

We have upgraded python from 3.7 to 3.9.8 in our project and for some reason a test stopped working. At a place of execution of a query on a database. That's the error that we receive:

RuntimeError: Task <Task pending name='anyio.from_thread.BlockingPortal._call_func' coro=<BlockingPortal._call_func() running at /python3.9/site-packages/anyio/from_thread.py:187> cb=[TaskGroup._spawn.<locals>.task_done() at /python3.9/site-packages/anyio/_backends/_asyncio.py:629]> got Future <Future pending cb=[Protocol._on_waiter_completed()]> attached to a different loop

Here's a stack:

/python3.9/site-packages/sqlalchemy/ext/asyncio/engine.py:457: in execute
    result = await greenlet_spawn(
/python3.9/site-packages/sqlalchemy/util/_concurrency_py3k.py:134: in greenlet_spawn
    result = context.throw(*sys.exc_info())
/python3.9/site-packages/sqlalchemy/engine/base.py:1614: in _execute_20
    return meth(self, args_10style, kwargs_10style, execution_options)
/python3.9/site-packages/sqlalchemy/sql/elements.py:325: in _execute_on_connection
    return connection._execute_clauseelement(
/python3.9/site-packages/sqlalchemy/engine/base.py:1481: in _execute_clauseelement
    ret = self._execute_context(
/python3.9/site-packages/sqlalchemy/engine/base.py:1845: in _execute_context
    self._handle_dbapi_exception(
/python3.9/site-packages/sqlalchemy/engine/base.py:2030: in _handle_dbapi_exception
    util.raise_(exc_info[1], with_traceback=exc_info[2])
/python3.9/site-packages/sqlalchemy/util/compat.py:207: in raise_
    raise exception
/python3.9/site-packages/sqlalchemy/engine/base.py:1802: in _execute_context
    self.dialect.do_execute(
/python3.9/site-packages/sqlalchemy/engine/default.py:732: in do_execute
    cursor.execute(statement, parameters)
/python3.9/site-packages/sqlalchemy/dialects/postgresql/asyncpg.py:457: in execute
    self._adapt_connection.await_(
/python3.9/site-packages/sqlalchemy/util/_concurrency_py3k.py:76: in await_only
    return current.driver.switch(awaitable)
/python3.9/site-packages/sqlalchemy/util/_concurrency_py3k.py:129: in greenlet_spawn
    value = await result
/python3.9/site-packages/sqlalchemy/dialects/postgresql/asyncpg.py:386: in _prepare_and_execute
    await adapt_connection._start_transaction()
/python3.9/site-packages/sqlalchemy/dialects/postgresql/asyncpg.py:694: in _start_transaction
    self._handle_exception(error)
/python3.9/site-packages/sqlalchemy/dialects/postgresql/asyncpg.py:662: in _handle_exception
    raise error
/python3.9/site-packages/sqlalchemy/dialects/postgresql/asyncpg.py:692: in _start_transaction
    await self._transaction.start()
/python3.9/site-packages/asyncpg/transaction.py:138: in start
    await self._connection.execute(query)
/python3.9/site-packages/asyncpg/connection.py:318: in execute
    return await self._protocol.query(query, timeout

Any idea if it's related to asyncpg, sqlalchemy, pytest or python? I'm not sure where to follow up with this error.