After "incompatible card" error messages whilst shooting on 6 different 8GB P2 cards I sent my camera to Panasonic NJ for a review and estimate. They found nothing wrong with the camera but would replace 2 card reader components for just under a thousand bucks.
Advice here on the COW got me to test record with my 6 cards at a rental house with another HVX200 and it seems one of my cards is bad. Here is the odd thing: after the "bad" card invoked the "incompatible card" error message in the rental house camera, I reinserted a "good" card again and THAT one invoked the error too. I was able to in-camera reformat the "good" cards that invoked the error but not the troublesome card.
I turned the camera off, waited a minute, and tried the "good" cards, they all worked fine. The bad one was still bad, and would not reformat. So I shipped that bad card to Panasonic to join my camera, where they said they'd test it. I received an estimate of over 200 bucks to replace that card.
My suspicion is that the bad card freaked out the camera's system and caused good cards inserted afterward to invoke error messages. When I was shooting and originally had the problem, and when testing before shipping the camera to Panasonic, I never thought to "reboot" the camera after receiving an error message between cards. The rental house guys agreed this was possible. The Panny service guy said it was not possible to be sure and to replace the camera components anyway even though he tested them as working.
I cannot easily afford the camera repair and would simply junk the bad card... so my query is to all here: what of this theory that a bad card can freak out the camera system, requiring a shutdown before resuming operation? I know now there's no way to further test since my stuff is at Panasonic, but yur opinions will help me decide next steps.
Follow-up: I'm getting the camera back as is, Panny is saying it is more than likely the bad card that caused a camera error, given the cards test I did at the rental house. And they are replacing the bad card.
If further testing / shooting adventures bear out another story, I will share it for anyone who is having similar issues.