Did creepers change?

I've noticed for the last few weeks that every night I've had at least 3 creepers per chunk spawn every night. They also don't die as fast as they seemed to a few months ago. My husband has also commented that they blow up faster than before. As well after we've run away a distance that used to calm them they still explode. Im not sure if this is a bug or something changed that we didn't know about?