Looks like rumors and disinformation spreaded by Anton Rozenberg - former Telegram developer. Russian journalists refer to his Facebook post[1]. IIRC, Rosenberg and Durov had some serious conflict. I've seen article on Medium[2] (earlier with unblurred screenshots) and Rosenberg seemed to me not quite adequate person.

[1] https://www.facebook.com/id77777/posts/10154846872521076 (Russian)

[2] https://medium.com/@anton.rozenberg/pavel-durov-sued-senior-...