Detailed description of issue
Placing one annotation results in the creation of multiple XML Tags in the XFDF String even if there is a single item visible on the annotations
Loading the provided document into our demo PDF.js Viewer Demo | PDF.js Express
and getting the annotations on the document, there seems to be multiple link annotations that are in the 2nd page:
One method would be to delete all the annotations that are inside the document when the document and annotations are loaded. Example in this guide here: