The audio back button has slowly stopped working entirely and the voice command button is fairly intermittent. I press them and get no response.
I've seen on other forums that this may be a fairly common issue.
Is there a common fix for this?

I'm probably going to send the car in for service to fix this, is there any chance it might be warranty covered since it may be a known issue?

 

It should be under warranty. Mine broke the moment I bought the vehicle. Run to dealership and get it fixed under warranty with no cost. I am in California.