Aiogram событие mention (в entities) не возвращает user

for en in message.entities:
    if en.type == 'mention':
        logging.info(en.as_json())
        user_receiver = en.user
        command = command.split('@')[0].strip()

ошибка:

AttributeError: 'NoneType' object has no attribute 'id'

mention в логах:

{"type": "mention", "offset": 4, "length": 12}