Thank you for writing.
Sounds like loading on demand is enabled and the node has no children but its LoadedOnDemand property is not set to true. Please take a look at this help article
If that is not the case, please write back with some more details about your issue. A sample project demonstrating the problem will be most helpful to quickly identify and resolve the issue.
If you have any other questions, please contact me again.
the Telerik team