Restarting the cockpit-ws is an hack just to force the reload of the web page. I really dislike it (see also Why cockpit is not restarted).
At least after applying updates in the Software Center, we could check if the UI and the API are at the same version. If it is not true, warn the user and say “hey, reload your page (Ctrl+Shift+R)”.
I’m not sure about “only once” but I agree it is rare enough to not require an immediate change. However let’s keep it in mind for future releases.
We cannot forget it! And also the QA team has to be aware of possible regressions in this area.