From the description provided it seems that the collection used as a ViewModel for the control does not support collection change notification when its items change.
In order for me to investigate the issue further I would need a sample project demonstrating the described scenario.
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.