Iron golem after it kills a mob it will continue to swing it's arms at it even though it is dead

Put the summary of the bug you're having here

What I expected to happen was...:
Iexpected the golem to kill a spider and continue to move along.
What actually happened was...:
The golem just continued to attack the spider even though it already died.

Steps to Reproduce:
1. make iron golem the normal way (iron block in T shape and pumkin on top)
2. spawn a mob or wait till night time(tested mine in a village though i made the golem)
3. Watch it kill a mob, and see it continues to attack it stand there.