You may want to insist such would force them to release, but the source citation for the data is the 2018 article. You may want to be sure it’s actually a “leak”.
I expect data release IS likely imminent. But I doubt this is that. I doubt Kazakhstan was on the list of reviewers, and they would have no source to backup their claim of those numbers. Their journal would be doing it wrong not to have verified their source for critical data.