I am having this issue as well, but I am getting this message in the console:
18:05:16 CONSOLE: [INFO] EntityGolemBase['Clay Golem'/7282, l='world', x=172.50, y=55.50, z=1036.50] was killed by null (outOfWorld)
18:05:16 CONSOLE: [INFO] EntityGolemBase['Clay Golem'/7284, l='world', x=170.50...