Onebox caching is absolutely necessary for external content and there is no expectation that it will be refreshed. I meant internal Oneboxes. As I mentioned in the example above, the Onebox created by a user is expected to be updated on all sites by changing the person’s biography.
Also, Oneboxes should be cached for internal content, and this is necessary to reduce the load, but maybe it is not bad to have internal Oneboxes indexed somewhere, and if the source record changes, an update task will be scheduled for them.
In the current situation, if the discourse updates the formatting of the Onebox changes (for internal cases), in the old posts it will still be displayed with the same pattern. This problem will be solved if we cache the content of the Onebox as JSON in the post and format it by the client.