Iron golem causes lag when it can't attack its enemies

The bug

When an Iron Golem is caged with line of sight to the target mob but can't attack due to blocks being in the way it creates large amounts of server lag.

Attached in a video of the bug, 1st part is the lag subsiding after kill the iron golem, the second part is the lag subsiding after killing the pillagers.

Video

kill iron golem -kill pillager.mp4