我有一个函数，它有一个半长时间运行的会话，用于处理一堆数据库行...在某个时刻，我希望重新加载或“刷新”其中一行，以确保状态没有发生任何变化。大多数时候，此代码工作正常，但我不时会遇到此错误

sqlalchemy.exc.InvalidRequestError: Instance '<Event at 0x58cb790>' is not persistent within this Session

我一直在阅读状态，但不明白为什么一个对象会停止持久化？我仍然在会话中，所以我不知道为什么我会停止持久化。
有人能解释一下是什么导致我的对象在会话中“非持久化”吗？在此之前我没有对该对象进行任何写入。
下面的 db_event 是将变为“非持久性”的对象

async def event_white_check_mark_handler(
    self: Events, ctx, channel: TextChannel, member: discord.Member, message: Message
):
    """
    This reaction is for completing an event
    """
    session = database_objects.SESSION()
    try:
        message_id = message.id
        db_event = self.get_event(session, message_id)
        if not db_event:
            return
        logger.debug(f"{member.display_name} wants to complete an event {db_event.id}")
        db_guild = await db.get_or_create(
            session, db.Guild, name=channel.guild.name, discord_id=channel.guild.id
        )
        db_member = await db.get_or_create(
            session,
            db.Member,
            name=member.name,
            discord_id=member.id,
            nick=member.display_name,
            guild_id=db_guild.discord_id,
        )
        db_scheduler_config: db.SchedulerConfig = (
            session.query(db.SchedulerConfig)
            .filter(db.SchedulerConfig.guild_id == channel.guild.id)
            .one()
        )
        # reasons to not complete the event
        if len(db_event) == 0:
            await channel.send(
                f"{member.display_name} you cannot complete an event with no one on it!"
            )
        elif (
            db_member.discord_id == db_event.creator_id
            or await db_scheduler_config.check_permission(
                ctx, db_event.event_name, member, db_scheduler_config.MODIFY
            )
        ):
            async with self.EVENT_LOCKS[db_event.id]:
                session.refresh(db_event)                ###########  <---- right here is when I get the error thrown
                db_event.status = const.COMPLETED
                session.commit()
                self.DIRTY_EVENTS.add(db_event.id)

            member_list = ",".join(
                filter(
                    lambda x: x not in const.MEMBER_FIELD_DEFAULT,
                    [str(x.mention) for x in db_event.members],
                )
            )
            await channel.send(f"Congrats on completing a event {member_list}!")
            logger.info(f"Congrats on completing a event {member_list}!")
            # await self.stop_tracking_event(db_event)
            del self.REMINDERS_BY_EVENT_ID[db_event.id]

        else:
            await channel.send(
                f"{member.display_name} you did not create this event and do not have permission to delete the event!"
            )
            logger.warning(f"{member.display_name} you did not create this event!")
    except Exception as _e:
        logger.error(format_exc())
        session.rollback()
    finally:
        database_objects.SESSION.remove()