A little while back my 1D II N developed a fault. Almost like banding but over all the frame. The oddest thing was that it only happened when the camera had been switched off for at least 24 hours, and only on the first shot in a series of shots. All the shots after this were fine. You could switch the camera on and off as many times as you wanted after this without seeing it again. The ISO setting had no relation to the fault, in fact these were taken at ISO 200
In the examples the original RAW .CR2 files were both around 7½ MB or so, but when saved as .jpg files the first shot saved as over 13MB and the second (normal shot) as about 6½ MB. These are 100% crops of the jpg files with no post processing applied.
As the camera is only 10 months old I contacted Canon about a warranty repair and ended up sending it down to Fixation in London, who repaired it and got it back to me in 9 days. They replaced the Imaging unit (I'm assuming this is the sensor), the A2 circuit board, the C circuit board and the D circuit board. All of which sounds like fairly major surgery and I hate to think what the cost of this would have been! Anyway, they did a first class job and it's performing better than new now. Anyone seen anything similar?