i've noticed that snow golems blink red when they throw a snowball at an enderman in the end that is rather near to them (about 5 to 15 blocks).
i have then separated them in a superflat testworld.
put one snow golem down, spawned one enderman in daylight (no other mobs around) and could reproduce the golem blinking then i noticed that the enderman does not.
whereas if the enderman blinks the snow golem does not.
i could also reproduce this with slimes