Hi Tapan,
Thank you for using Syncfusion products.
We have tried to reproduce the reported issue in our end, but it is working properly. We have created a sample for HTML file to PDF conversion in WebKit converter, it generates a PDF document properly. We were not able to reproduce the issue and we have shared the sample for your reference. Kindly please run the sample in your end and let us know the result.
Please refer the below links for more information,
Note : Please make sure all the pdf documents are close in your machine task manager.
If still you are facing an same issue, kindly provide more details such as complete input HTML file/URL (with all resources styles, scripts, etc.,), complete code snippet, product version to check the issue in our end. So, that it will be helpful for us to analyze and assist you further on this.
Regards,
Gowthamraj K