I have had creepers explode under situations without player interaction, or triggering.
ADDITIONALLY: It involes big lag spikes or freezes.
This is where skeletson shoot creepers and then the creepers explode.
It might be both the skeleton new AI/movement together with the Creeper AI/Exploding, that causes it.
The lag does seem to happen when skeletons are fighting eachother, and/or creepers.

This generally ends up thinking the mobs are still far away, and then they suddelny are in your face, and you are dead, and all items are gone.
This is a serious issue.
The Skeleton Ai, has severely impacted stability, of the game (lag, glitching through blocks, not able to hit them, moving around incredibly fast and walk around you).

This causes structures, and landscape, even even PROTECTED areas, walls, and CHESTS, to break and destroyed, and loosing any valuables, blocks, etc. despite all the defensive effort put into it, and even without any knowlege of it happening.

Basically at anytime, you can sit "safely" in your house, and then be blown to pieces because a creeper exploded on you, without you triggering him.