If I setup the richtextbox content through the UI as shown in P1.png and try to restore it by pasting the generated html, I get instead P2.png. Expected to be the same.
I attached the sample project. We're using the recommended settings to use the same html in telerik reports, but can't find the reference on your site, it used on the on this link http://docs.telerik.com/devtools/wpf/controls/radrichtextbox/import-export/features-import-export-settings#htmlformatprovider