Hello, I found edge case which shows PDF and Word watermark support is different.
When we set exactly the same color for page background and for watermark in PDF it will become invisible but word performs some logic which makes it visible.
Here is minimal code to reproduce this issue:
Document doc = new Document();
Color value = new Color(191, 191, 191);
doc.setPageColor(value);
TextWatermarkOptions options = new TextWatermarkOptions();
options.setColor(value);
doc.getWatermark().setText("ASAP", options);
doc.save("a.docx");
doc.save("a.pdf");