Bug? Clicking on "Yes" on an event you're already in moves you to end

Our playgroup sometimes takes seriously the order, in which people signed up because sometimes the spots are limited.
Just discovered this today, as i clicked on an event, that i did not notice, that i was already joined and was moved to last place.
There should be a verification if the current action would change the status, before actually setting status, as it changes the timestamp too.