Chosen Solution
This is a statement rather than a question. The latest iOS update is causing problems with early builds of those phones. Mine would act like the headphones were plugged in to the lightning port, even when not. My headphones would stop playing sound and the remote controls wouldn’t do anything. The phone volume buttons would say volume instead of headphones and the ear speaker wouldn’t do anything during a call. One last symptom was that when looking at one of your voicemails, the bottom left control for that particular VM said “Audio” instead of “Speaker”. Apple just replaced mine under warranty.
Mine was replaced out of warranty.
Your lucky you had yours replaced under warranty , I hope a fix is found for this issue, maybe next update will resolve problem for people who can’t get replaced under warranty
