Sound coming out both speakers and headphones

[eclay]

Hello,

I've noticed that when I attempt to plugin headphones to my pinebook and play a video that sound still comes out the internal speakers and the headphones.  Is this how it's supposed to work?  Any ideas how to troubleshoot or fix this?

I'm running the default ubuntu mate on it and I poked around in the sound settings and didn't find anything there that looked like the answer to this problem.