Period task dispatch abnormally

[belongwqz]

Summary:

Period task dispatch abnormally .

• Celery Version: 5.1.2
• Celery-Beat Version: 2.2.1

Exact steps to reproduce the issue:

1. a period task which use a crontab schedule, for example "1 06 * * *"
2. change the task to use another crontab schedule, for example "1 08 * * *"
3. after the time I save task, the task dispatch immediately that not match it's crontab schedule.

The problem is random and difficult to reproduce

Detailed information

the celery-beat log:

[2021-09-02 14:13:20,046: INFO/MainProcess] DatabaseScheduler: Schedule changed.
[2021-09-02 14:13:20,529: INFO/MainProcess] Scheduler: Sending due task xxxx(xxx.celery_auto_task)