Downloaded file allows editing on free text fields. In the browser preview it behaves correctly

[saurabhPimplapure1]

I have a custom application where we open a pdf file in pdf.JS on click of a button. PDF file has some clickable external links and free text fields in PDF. When rendered in browser preview, external links work correctly and free text fields are not editable. This behaves correctly.
However, When the file is downloaded from the preview window and saved locally, Observed behavior as mentioned below across browsers.
Actual Result:-
Chrome(121.0.6167.161) :- Free text fields are not editable after download.
Firefox(122.0.1 ):- Free text fields are editable after download.
Edge(121.0.2277.112):-Free text fields are editable after download.
Expected Result:-
Free text fields should not be editable after downloading.

Below is the error snapshot

Kindly suggest how to solve this issue.