[wirthy]

This just happened to me for the first time. I was listening to my phone via headphones last night. When I removed the headphones this morning, the headphone icon stayed on and no sound would come from my phones speaker. Re-inserting the headphones brought up the voice command icon. Sometimes inserting the headphones would cause my phone to redial my last call.

On advice from this thread, I re-inserted the headphones several times (dozen?) and finally the headphone icon went away. Perhaps cleaning the headphone jack with a can of compressed air will help. I do keep my phone in my pocket, so I assume lint and dirt could cause problems.