I think the fact you're assuming that Iran would be capable of such thing like hypersonic missels while they are very undeveloped especially in this kind of technology/power. Nobody knows for sure that's true. Many Govs have technologies and powers which many are not aware at all so this in itself it's true that we do not know.
As for what Russia goes they were never trustworthy, nobody can except Russia to play upon their word and literally trust them. So anything that Russia dose especially in those days times it's not a surprise at all.