RadButton with ButtonType="ToggleButton", ToggleType="CheckBox" or ToggleType="Radio" in lightweight mode, renders the icons and the text labels at incorrect position.

For the time being, you can use the following CSS as a workaround:

.RadButton.rbCheckBox span.rbText,
.RadButton.rbRadioButton span.rbText,
.RadButton.rbToggleButton span.rbText {
    vertical-align: initial; /* FF and Chrome */
    vertical-align: auto; /* IE */
}

button.RadButton {
    vertical-align: initial;
    vertical-align: auto;
}