I am not sure, what is the page/link in question, if it is a
www.avast.com or my.avast.com.
This is how it works:
When you have a link, without any locale (e.g.
https://my.avast.com), you will be redirected to a locale estimated by your current location. This is estimate is based on your IP so it is not 100% perfect, but i most cases it works pretty well.
All recommendation links are generated without the locale.
You can change your locale using the locale icon (on
www.avast.com or the login page), or the Settings icon in my.avast.com. Once you will do that, your URL will change and will include the locale, e.g.
https://my.avast.com/es-es for Spanish.
If your are logged in to your account, every time you visit the site, it will be in your chosen locale.
If you will take this link and send it to someone, the page will be shown in the locale defined in the url.