We suppose that this could be caused by the settings applied to the RadToolTip/RadToolTipManager and the way they are used in this particular scenario.
In order to be able to help we will need to examine your code. Please, open a new support ticket and send us a fully working, sample project (including DB if needed) along with detailed explanation of the desired behavior. Once we receive it we will locate the problem and we will do our best to help.
the Telerik team