Bizarre audio issue with HPX170

Hi,
I've had my Panasonic HPX170 for a couple years now and I just noticed the other day when I tried using it that the in-camera mic and neither of the XLR inputs were registering any audio levels in the shooting mode that I usually use, F5 "Cine V." As it turns out, only F2 "Fluo." and F3 "Spark" register audio levels. I haven't changed anything at all in the settings. I tried looking at the different setups in the menu, but everything looks the same between them as far as audio settings, so I have no idea why all of a sudden only F2 and F3 show audio levels.
I've tried everything I can think of... any clues out there??
thanks.