Left audio channel problem
 

I have a relatively new XL2 with a stock microphone, and I have an interesting issue that happens with the Left Channel audio after the camera is left on for a period of time.

The channel slowly starts to deteriorate, causing a serious balancing issue. Soon, it's just the Right Channel that captures audio. This is an issue for longer shots - where it may just start to die in the middle of them, forcing me to retake and roll the dice again. What seems to fix the problem temporarily, is actually disconnecting the microphone then plugging it back in. I give a tap on the end of it and check the viewfinder to see if it's balanced again.

This problem is most apparent once the camera is on for an excess of 30 minutes.

Is this a known issue with XL2s? Anything that I may be particularly doing wrong?

Thanks in advance.