No, this is definitely not normal. It seems to be a serious issue, however we have not observed it before and I am not able to identify it by using the provided information. I noticed that you are using a quite old version of RadControls for WinForms. That is why I recommend that you try our latest release - Q2 2012 SP1. If the issue continues to appear, please send us your application and we will research the case further.
Should you have any further questions, do not hesitate to ask.
the Telerik team