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<!--- Complete *all* sections as described, this form is processed automatically -->

##### 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

```

}
                    worker_prc = WorkerProcess(self._final_q, task_vars, host, task, play_context, self._loader, self._variable_manager, plugin_loader)
                    self._workers[self._cur_worker] = worker_prc
                    self._tqm.send_callback('v2_runner_on_start', host, task)
                    worker_prc.start()
                    display.debug("worker is %d (out of %d available)" % (self._cur_worker + 1, len(self._workers)))
                    queued = True
                self._cur_worker += 1
                if self._cur_worker >= rewind_point:
                    self._cur_worker = 0
                if queued:
                    break
                elif self._cur_worker == starting_worker:
                    time.sleep(0.0001)
            if isinstance(task, Handler):
                self._pending_handler_results += 1
            else:
                self._pending_results += 1
        except (EOFError, IOError, AssertionError) as e:
            
            display.debug("got an error while queuing: %s" % e)
            return
        display.debug("exiting _queue_task() for %s/%s" % (host.name, task.action))
    def get_task_hosts(self, iterator, task_host, task):
        if task.run_once:
            host_list = [host for host in self._hosts_cache if host not in self._tqm._unreachable_hosts]
        else:
            host_list = [task_host.name]
        return host_list
    def get_delegated_hosts(self, result, task):