Add the RadRangeSlider, or RadSlider inside a ScrollView, for example at the end of the ScrollView. Then start scrolling the content inside the ScrollView. Try sliding the thumb of the RadRangeSlider or RadSlider, The thumb locks and will no longer move. The issue happens only on Android and iOS. 

On Android you can unlock the thumb by tapping on it, while on iOS there isn't an option, the thumb does not move.