We have discovered a bug involving unranked games. It would seem that although unranked games are being tracked as such, they nonetheless still affect your rating as if they were ranked. So, as it stands now, ALL games will affect your player rating. Note, however, that winning/losing to a guest player NEVER affects your rating.
We will have this issue corrected in our next release. Since all previous games have affected your score, we will make a change to the database to reflect this when we make the update, crediting all of your current unranked games as ranked ones.
Also note that in order to play team games with randomly assigned teams, you must set the game to "unranked". This is also a bug and will be corrected in next release as well.
We apologize for the inconvenience and will have this fixed for you very soon!