Creepers may explode when mobs are fighting each other without player nearby.

STR: Make simple 4x4 room with iron golem, bunch of skeletons and creepers. Let them fight.

If it is intended behaviour, it is extremely annoying. I got villager killed by creeper explosion outside the building without me even noticing it, so I couldn't revert to backup.

The workaround is to never let Iron Golems fight hostile mobs (via fences and lighting). However, it kinda defeats the point of Iron Golems existing in first place.

PS:

"One of the biggest game design decisions in Minecraft is that all (well, most) negative things that affect the world or the player should happen near the player, and be clear to the player. That’s why creepers only explode near players, and that’s why fires stopped spreading indefinitely."

https://notch.tumblr.com/post/8208212863/the-psychology-of-the-reticle-and-the-feeling-of