Technically, they just say that a Wagner linked Telegram channel said it got shot down. They're probably waiting for better proof/additional sources before they take the full step of saying it was shot down themselves (at which point I think it'd get added to the headline).
Because the only source for that (at present) is the Wagner Group, who have a (dead) dog in the fight and are not bastions of truth. NYT will be trying to confirm it before saying so.