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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 
```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### 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

```

for target_host in host_list:
                                
                                
                                
                                
                                
                                if original_task.action != 'set_fact' or cacheable:
                                    self._variable_manager.set_host_facts(target_host, result_item['ansible_facts'].copy())
                                if original_task.action == 'set_fact':
                                    self._variable_manager.set_nonpersistent_facts(target_host, result_item['ansible_facts'].copy())
                    if 'ansible_stats' in result_item and 'data' in result_item['ansible_stats'] and result_item['ansible_stats']['data']:
                        if 'per_host' not in result_item['ansible_stats'] or result_item['ansible_stats']['per_host']:
                            host_list = self.get_task_hosts(iterator, original_host, original_task)
                        else:
                            host_list = [None]
                        data = result_item['ansible_stats']['data']
                        aggregate = 'aggregate' in result_item['ansible_stats'] and result_item['ansible_stats']['aggregate']
                        for myhost in host_list:
                            for k in data.keys():
                                if aggregate:
                                    self._tqm._stats.update_custom_stats(k, data[k], myhost)
                                else:
                                    self._tqm._stats.set_custom_stats(k, data[k], myhost)
                if 'diff' in task_result._result:
                    if self._diff or getattr(original_task, 'diff', False):
                        self._tqm.send_callback('v2_on_file_diff', task_result)
                if not isinstance(original_task, TaskInclude):
                    self._tqm._stats.increment('ok', original_host.name)
                    if 'changed' in task_result._result and task_result._result['changed']:
                        self._tqm._stats.increment('changed', original_host.name)