To add to the above, I did the following testing today inside a warm house:
I put the camera in a small ice chest with an ice pack and turned on the cooler. Took a while, but it finally started dropping frame information. Took the camera out and let it warm up and it quickly resumed normal operation. Tried to repeat this, but it ran for quite a while with no problems. Noticed that although the camera sensor temp was indicating -15 C, the camera body was very warm.
I then put the camera in the refrigerator's freezer for about half an hour. The camera's body was very cold to the touch (like it gets when I'm outside observing at night at this time of year) and there was noticeable moisture on it. Plugged it in and the frame dropping problem was there. Left it plugged in while it warmed up and after a bit, it started working normally. Turned the cooler on and put it in the ice chest, but it's still to warm for the camera sensor to get to the target temp of -15 C (e.g., now indicating -10.5 C with the cooler at 100%). Also, camera body is pretty warm. No dropped frames.
I am now wondering if the problem is dew or dew+temperature related. The 2 recent nights when it worked fine were pretty dry -- no dew issues. Last night and the other previous night where the camera had major problems were not quite as cold, but there was a lot of dew.
