Imam Bukhari narrates: As-Salt bin Muhammad narrated to us, he said: Mahdi informed us, from Wasil, from Abi Wa'il, from Hazrat Hudhaifah (may Allah be pleased with him),
he saw a man, he was not making complete Ruku' and complete Sajdah, when that man finished his prayer, Hazrat Hudhaifah said to him: "You have not prayed," and I think he said: "If you died (while praying in this way), you would die upon other than the Sunnah of Sayyiduna Muhammad ﷺ."
Reference: Sahih Al Bukhari 389