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##### SUMMARY
After upgrade from 2.9.10 to 2.9.11 I noticed the module 'group_by' is reporting 'changed'.
This is because this change in #69860 
The problem is that it is reporting 'changed' even with `changed_when: false` added to the task.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
group_by

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.9.11
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
Ubuntu 18.04 (control and target host)

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
As an example use the task:
```
- group_by:
    key: "os_{{ ansible_facts['distribution_file_variety'] }}"
  changed_when: false
  register: groupby

- debug:
    msg: "{{ groupby }}"
```

```yaml
TASK [group_by_os : group_by] *******************************************************************************************************************************
changed: [srvd-test04]

TASK [group_by_os : debug] **********************************************************************************************************************************
ok: [srvd-test04] => 
  msg:
    add_group: os_Debian
    changed: true
    failed: false
    parent_groups:
    - all

PLAY RECAP **************************************************************************************************************************************************
srvd-test04                : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0 
```

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##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
The task should always return `changed: false`

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
The task return `changed: true`
<!--- Paste verbatim command output between quotes -->
```paste below

```

"""Closure to wrap ``StrategyBase._process_pending_results`` and invoke the task debugger"""
    @functools.wraps(func)
    def inner(self, iterator, one_pass=False, max_passes=None, do_handlers=False):
        status_to_stats_map = (
            ('is_failed', 'failures'),
            ('is_unreachable', 'dark'),
            ('is_changed', 'changed'),
            ('is_skipped', 'skipped'),
        )
        
        prev_host_states = iterator._host_states.copy()
        results = func(self, iterator, one_pass=one_pass, max_passes=max_passes, do_handlers=do_handlers)
        _processed_results = []
        for result in results:
            task = result._task
            host = result._host
            _queued_task_args = self._queued_task_cache.pop((host.name, task._uuid), None)
            task_vars = _queued_task_args['task_vars']
            play_context = _queued_task_args['play_context']
            
            try:
                prev_host_state = prev_host_states[host.name]
            except KeyError:
                prev_host_state = iterator.get_host_state(host)
            while result.needs_debugger(globally_enabled=self.debugger_active):
                next_action = NextAction()
                dbg = Debugger(task, host, task_vars, play_context, result, next_action)
                dbg.cmdloop()
                if next_action.result == NextAction.REDO: