When using the Aspose.Pdf.dll ( version 25.1 and 25.5) , calling the Aspose.Pdf.Facades.Form.ImportFdf method results in error "unable to cast object of type ‘aspose.pdf.annotations.widgetannotation’ to type ‘aspose.pdf…...compatibility issue between the FDF data and the PDF form fields. Here...malformed or contains unexpected data types, it could lead to casting...