I was surprised tonight when I turned the G6 on to take a picture of my friends while indoors. I had the camera in the M mode. I then set up the ISO, aperture, and shutter speed settings to the ones that I wanted. I didn't realise that the flash mode was still in the no-fire mode, so the picture turned out too dark for the first shot with the new settings. With the camera still holding the new settings, I then pressed the button to change the flash mode from no-fire to compulsory-fire. But the camera was stuck in the no-fire mode, even when I kept pressing the button used to select the flash mode. This was really annoying. Eventually, I just turned the camera off, then back on again....and only then I was able to change the flash mode.
I thought I'd just post this experience in case anybody else has come across the same thing. I'm just hoping that my camera is ok, and that it was a rare glitch.