Attacking while stunned

Back in a while i had this issue and i believe it is still happening... I stun someone, he can still attack me / cast abilties This bugs me alot since it is not supposed to work this way ruins my play

Those are 2 quick videos (Sorry for bad quality - got a potato pc) one with normal speed : https://youtu.be/VTo6zhnfHCE another with .5x speed: https://youtu.be/cffOsmLg1p0

Would like to have explanation too