On our site weekly re-occurences result in daily re-occurences no matter which days we check. Please, see screenshots below for an example. I am afraid this is not reproducible in the current demo. Neither any errors in the webgui log file. But I suspect this could be related to i18n (we are running German language). Names of days in the event edit template have not been translated yet. Internally, German names may be used. Just a guess...