Hi Sumimol,
Greetings from Syncfusion.
We are able to reproduce the issue in your version 15.3.0.26. However, we have fixed this issue and the fix has been included in our release version 16.2. So, we request you to upgrade to our latest release version 17.2.0.28 which has more bug fixes, enhancements and features. Latest version can be downloaded from following link.
You can also refer the NuGet from following link to your application to ensure the same.
Please check and let us know if issue is resolved at your end after upgrading to latest version.
Regards,
Abirami