Did they change how kayn's ult works?

Hi ! I am posting for my friend because he is annoyed but while playing kayn for the past 4+ games my friend has somehow been able to be killed by champs while he in ulted into another, as far as I know the only thing that can damage kayn while ulted is a dot or debuff but my friend died against a graves after ulting into him? he didn't come out then die he died while inside him