podcast app stops playing, skips, jumps backward, forward, activates Siri...

So,

Had a problem with my original iPhone 6 and was given a replacement. After a full restore I've had nothing but frustrations with audio playback. I'll listen to podcasts or streaming radio, and just as soon as i put the phone in my pocket, it will stop playing, prompting me to pull it out and hit play, podcast will start, then stop as soon as it goes back into my pocket. Either that, or Siri might start up, or maybe it'll jump to 1.5x speed, or maybe it'll jump back a few episodes of whatever podcast I'm listening to. I have to insist I'm not doing anything outside of any normal maneuvering, and nothing that would have prompted my original iPhone to behave like this. And can I just say, it's rather infuriating--into the pocket out of the pocket start stop start skip stop Siri start stop. Any ideas anyone? Will try another full restore tomorrow, but it being a replacement, I'm wondering if the refurbishment process wasn't done particularly well.