I have a C6833 and this problem started a few months back with my device.
Now it happens about every time I pause the music. When I hit play or resume the audio is coming from the internal speaker so I have to unplug the cable and plug it back in and that solves the problem at least for the moment. Some days my device does what it suppose to do just great. And other periods it just sends the stream back to the internal speaker all the time whenever I pause the music.
I have flashed the latest .108 but problem still exists. It might be some error with the hardware what do I know. For now I won't take the time to send it in for service. Perhaps I will send it to repair right before my warranty expires just to make some use of it
I use the stock headphones, and some Apple just some generic Apple earphones that you receive in the box when you buy an Iphone 5 or later