I found the root of the problem. This behavior is apparently related to the MS Edge browser. Since I decided to save my password the first time I launched the app and logged in, every time I load a sample template the "pdf-password" property is automatically filled with the save password used in the login screen. Once I deleted the saved password from the profile I no longer experience the problem. By the way, I tested in Firefox and Chrome also. These two browsers do not present the problem.
Thank you for your help.