Facebook Test User API login url working or not randomly
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I have wrote a desktop app, that holds FB applications data and lists test users.
I want to open a browser with new profile (browser profile, not FB, because to session problems in PHP facebook API - I want to be not in my a app session on my domain).

But the problem is, that facebook login URL is working or not randomly.
I have tried Firefox & Chrome. 

Firefox with `-no-remote`, `-p "RANDOM_PROFILE"`, and also `-CreateProfile` executing before execution to open url with that profile.

Chrome with `--profile-directory="RANDOM_DIR"` (directory created earlier).

Managing browser profiles works good in both browser. But in most cases, opening browser with Facebook Test User login URL, just redirects me to main page.

Also, i have created a some PHP pages:

 - one redirecting after a while to login URL by window.location
 - one redirecting after a sleep by header('Location: ...') to login url
 - one with `<a href...>` tag to login url.

Third option is the only one working, but it works in about 20% cases (sometimes clicking many times on that link & opening multiple times in new tabs is working)

How to do launch of a new browser instance with facebook login URL where loging works fine ?

Edit: my loging URL's are always fetched from FB very shortly before login try, so they aren't expired.