Ringer playing through both headphones and speaker

I like to listen to music at work. However, I received a call and I realized that it was coming from both the earphones and the speakers on the phone. I don't want to leave it in silent mode because my phone is not in sight and I can't feel the vibrate on the desk. The problem only occurs only for calls with the Apple earphones. I have used another pair of earphones and this problem has never occurred before.

Does anyone know why it is playing through both the speakers and earphones? Is there a solution to this? I've looked through settings and I wasn't able to find any settings to change this.