I have downloaded the latest copy of Aspose.Words & Aspose.PDF and the watermark functionality does not seem to work correctly anymore.
Please have a look at the documentation here:
https://docs.aspose.com/words/net/working-with-watermark/
In a previous version of words the watermark looks fine, but in the latest version its squashed together.
Also the PDF output doesnt work correctly using Aspose.PDF or using the built in export facility into words:
doc.Save("words_test.pdf", SaveFormat.Pdf);
Regards
Chris