Hi Giacomo,
Thank you for using Syncfusion products.
We have tried to reproduce the reported content missing issue on our end, but it is working properly. We have created a sample and tried to convert the provided URL to pdf document, it generates a PDF document and all the content are rendered properly. We were unable to reproduce the issue and we have shared the sample and output document for your reference. Kindly please run the sample on your end and let us know the result.
If still, you are facing the same issue, kindly provide more details such as environment details (OS, Bit version, culture settings, RAM, etc.,), modified sample, product version to check the issue on our end. So, that it will be helpful for us to analyze and assist you further on this.
Regards,
Gowthamraj K