Hi, My first post here! My K1S has a similar fault, but I am not convinced its entirely down to the sd card. It stops recording with a beep, and the displays "rec" goes green. A few seconds later, it says "Recording Started" and the rec goes red again, until the next time. I have tried several different cards, all meet the specifications, and all give similar results. They are two different 32GB Samsung cards, a 32GB Kingston, a 64GB SanDisk and a 16GB SanDisk . They are all speed Class 10 with a UHS speed class "3 in a U" symbol and have write speeds of 85 or 90 MB/s. The best of them was the 16 GB SanDisk. All of these cards give excellent results in a Panasonic SDR-H86 camcorder. There was just one bad soldered connection inside, it was on a small button battery near the power input socket, but it made no difference. Don't know why that should be there when there is a big battery in there!
I think it may be due to insufficient internal buffer memory. Recordings go first to a buffer in bits then to the sd card in one go. I think that's how it works.
My daily journey is 20 odd miles of the M3, through the ****** road works with a couple of miles of A roads each end. It can sometimes go for a couple of weeks without problem. But if there is any accident on the M3, it gets blocked for hours (because they have done away with the hard shoulder, don't get me started on that) so I then use B roads across country, avoiding the bunged up M3 and clogged A roads. The problem then will always show at least 4 or 5 times every time on that journey. The view on the motorway is fairly "simple", but the view on the B roads is "complicated", with tree lined country lanes and residential roads, so the B roads make it work harder, but it cant do it, so stops recording to recover. Wonder if anyone else has noticed the problem seems to be related to the amount of information it has to record at any one moment ?