Hey there,
Unfortunately I cannot reproduce your issue in Adobe or any other reader (with my own code - I can reproduce the issue with the document you sent me.). I believe this is an issue with the way you are using the API.
How are you loading the document? Please note that getAnnotationsList will not return any annotations that already exist in the opened document (PDF.js Express cannot parse annotations out of existing documents, unless you use the extract rest API)
Here is an upgrade guide - Migrate from PDF.js Express to PDFTron webviewer | PDF.js Express SDK (the APIs are the exact same)
Thanks!
Logan