Does long-polling work always even if the user switches app?

I have an application which sends notification to its subscribers through telegram.
For someone to subscribe, he needs to add his request in my website and after that, to identify his self, he needs to start a conversation with my bot using a secret code generated by the server.
For example, whenever he completes his request he should click a button which leads him out of my website and to telegram's chat (using <a href="https://t.me/mybot?start=abcd"></a>), in the background, the website is making long-pool requests to the server to check whether the server received a notification from telegram with this secret code abcd and to get the chat id assosiated with the request so it could store the request with this specific chat id.
The process seems to work just fine for many users, but for minor amount of users it's not working, they are starting a conversation with my bot but not getting any feedback about a success. It seems as whenever they leave the website (or the browser) and follow the path of the link (https://t.me/mybot?start=abcd) straight to telegram app, the long-pool is being stopped.
does that happen sometimes when long-polling?