I don't see this behavior. Maybe I'm misunderstanding. I've attached a screenshot of what I see.
I'm going to close this since it's working as intended and was just based on a miscommunication -- the actions UI (above the comment text area) is not expected to show a preview of the effects of a change. Instead, the preview UI (below the comment text area) shows this preview information.
(If the preview UI misrepresents the effects of a change, that's a bug, but it appears to be working properly here, as circled.)