iPhone 6s Plus - my earbuds just shocked me

I went out for a walk today, listening to a podcast with my 6s Plus and the earbuds that came with the phone. Today was the first chilly day i've done this since getting the phone. At the end of the walk, just as I was getting out of my coat, while the podcast was still playing, something went wrong with the earbuds, and I received an electric shock in both ears. I immediately removed my earbuds. Not sure if some persperation got into the speakers, or what might have happened, but I'm wondering if this is a known problem?