This is indeed strange. I would suggest to check the Styling or content mixed-up on scrolling
troubleshooting article. If it does not help, you can try to isolate the problem in a sample project and send it to us for further investigation. You can check this blog post, which explains how to isolate a problem in a sample project.
As a side note - Do you have frozen columns?
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.