Using custom attr's in status updates doesn't work?

[CN91]

According to the docs we can reference playbook attributes inside the status updates.

Attributes enable you to:
Define contextual information that varies between runs (e.g., incident severity, priority level, customer type).
Trigger different tasks or workflows based on attribute values.
Create conditional logic in your playbooks for more sophisticated automation.
Maintain consistent data collection across runs.
Playbook attributes are visible to all run participants and can be referenced in status updates.
source: https://docs.mattermost.com/end-user-guide/workflow-automation/work-with-playbooks.html

However I can't seem to find the correct way to reference them so that they actually get filled with the current value when posting the status update.

So what is the way to use our own defined attributes in status updates?