Checklist

[x] I have verified that the issue exists against the master branch of Celery.
[ ] This has already been asked to the discussion group first.
[x] I have read the relevant section in the contribution guide on reporting bugs.
[x] I have checked the issues list for similar or identical bug reports.
[ ] I have checked the pull requests list for existing proposed fixes.
[ ] I have checked the commit log to find out if the bug was already fixed in the master branch.
[ ] I have included all related issues and possible duplicate issues in this issue (If there are none, check this box anyway).

Mandatory Debugging Information

[x] I have included the output of celery -A proj report in the issue. (if you are not able to do this, then at least specify the Celery version affected).
[x] I have verified that the issue exists against the master branch of Celery.
[x] I have included the contents of pip freeze in the issue.
[x] I have included all the versions of all the external dependencies required to reproduce this bug.

Optional Debugging Information

[x] I have tried reproducing the issue on more than one Python version and/or implementation.
[ ] I have tried reproducing the issue on more than one message broker and/or result backend.
[ ] I have tried reproducing the issue on more than one version of the message broker and/or result backend.
[ ] I have tried reproducing the issue on more than one operating system.
[ ] I have tried reproducing the issue on more than one workers pool.
[x] I have tried reproducing the issue with autoscaling, retries, ETA/Countdown & rate limits disabled.
[ ] I have tried reproducing the issue after downgrading and/or upgrading Celery and its dependencies.

Related Issues and Possible Duplicates

Related Issues

None

Possible Duplicates

Environment & Settings

Celery version: 5.1.2 (sun-harmonics)

celery report Output:

```shell software -> celery:5.1.2 (sun-harmonics) kombu:5.1.0 py:3.9.6 billiard:3.6.4.0 redis:3.5.3 platform -> system:Darwin arch:64bit kernel version:19.6.0 imp:CPython loader -> celery.loaders.app.AppLoader settings -> transport:redis results:redis://localhost:6379/0 broker_url: 'redis://localhost:6379/0' result_backend: 'redis://localhost:6379/0' deprecated_settings: None ```

Steps to Reproduce

Python Packages

pip freeze Output:

``` amqp==5.0.6 billiard==3.6.4.0 celery==5.1.2 certifi==2021.5.30 click==7.1.2 click-didyoumean==0.0.3 click-plugins==1.1.1 click-repl==0.2.0 kombu==5.1.0 prompt-toolkit==3.0.20 pytz==2021.1 redis==3.5.3 six==1.16.0 vine==5.0.0 wcwidth==0.2.5 ```

Minimally Reproducible Test Case

```python from celery import Celery app = Celery("celery_app", broker="redis://localhost:6379/0", backend="redis://localhost:6379/0") @app.task(bind=True, max_retries=10) def work(self): try: raise self.retry(countdown=2) except Exception: raise self.retry(countdown=2) if __name__ == '__main__': res = work.delay() print(res) ```

Expected Behavior

The task terminates when the max_retries=10 of retries is reached，And then throw an celery.exceptions.MaxRetriesExceededError

Actual Behavior

Multiple repeated tasks were received, and the number of tasks greatly exceeded the max_retries value. Procedure This causes the task to be executed multiple times. In addition, after testing, I found that the number of replication tasks increases with the increment of countdown.

celery / celery

Same task is copied multiple times and exceeding the `max_retries` parameter value #6931