@kuzmin_sergey by chance is their a public facing URL that I can test against? If you aren't comfortable posting here, please contact your AM and pass them the URL and they can send to me. Or save the HTML and send them the .html page so I can load locallly and try to replicate.
Your rule seems correct, the only thing I'd do is swap to check that event_type is defined before checking that it equals "session". Though I believe Tealium load rules has been enhanced to automatically check the variable existance before checking the value so I doubt that's it.