Radio button controlgroup leaves buttons in the down state

Radio button controlgroup leaves buttons in the down state

I've noticed that the buttons created in the Radio button controlgroup remains in the down state when you click on another button in the group. Inspecting the className of each of the buttons, I noticed that the selected button has ui-btn-active and ui-btn-hover-b, the untouched button has ui-btn-up-b, and any clicked on buttons have ui-btn-down-b. So whenever a button is clicked, it's set to ui-btn-down-b, and never changed back to ui-btn-up-b, leaving the button in the down state. Is this expected behavior? Thx.