This is reproducible with specific PDF files which use custom Encoding for the fonts of the field widgets. WORKAROUND: Change the font of VariableContentWidgets before editing the field value. You should additionally call RecalculateContent() method of these widgets if the value of their corresponding fields is not edited. The following method may be used for changing the font of all existing widgets in the document: private static void FixEncodingIssues(RadFixedDocument document) { foreach(Annotation annotation in document.Annotations) { VariableContentWidget widget = annotation as VariableContentWidget; if(widget != null) { widget.TextProperties.Font = FontsRepository.Helvetica; } } }