This behavior can be observed with the example below.

https://demos.telerik.com/aspnet-ajax/listview/examples/paging/pagingwithraddatapager/defaultcs.aspx

Enter a value for Page and click the Go button. Either the page will be updated to the expected page or the pager will fail to change the page. Clicking Go again usually seems to work if it failed. It may take a several tries to observe this behavior as it happens inconsistently.

If one wants to change the current page index one should provide a value for the CurrentPageIndex property. Example RadDataPager1.CurrentPageIndex=5;