This information in not enough, to give you any useful advice, especially after you can not replicate the issue.
Ask the person who reported the issue, to make a video how he is replicating the issue or to describe the exact steps needed to do so, thus we will be able to examine the steps and reproduce it at our side. Being able to reproduce it at our side we'll try to find what is causing this behavior and what are the steps to overcome it.
All the best,
the Telerik team
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