Iron Golem Doesn't Punch Me ?

What I expected to happen was...:
He Must Kill Me

What actually happened was...:
Iron Golem Doesn't Punch Me ?
Iron Golem not hit me ?
Iron Golem Haven't Hit Me ?
Iron Golem Tries to hit me but noting happen ?

( Bad English ( I am not English ) )
Steps to Reproduce:
Punch a Iron Golem in Gm Survival