GH4 and 14-140 stabilization issue

Summary of my experience with GH3 & 14-140mm.

Just got a new 14-140mm (f/3.505.6). Used it with GH3.

The video shows jitter. I shot hand held, OIS on, 1080/60p (which is what I always shoot), shutter speed 1/125. I held the camera still, aimed at one point, and shot about 1 minute. The jitter isn't a lot, but it's there. Sort of a slight quivering or vibration, just a couple of pixels. The focal length was about 60mm, and the jitter might well be worse at longer focal lengths. I usually shoot action video so this won't normally be a problem, but I don't like the idea of a built-in limitation. What if I do want to shoot stationary objects or scenes?

I later made some test vids at 140mm, OIS on. Handheld, the jitter was worse than at 60mm (as anticipated). The motion was larger (I shoot almost everything hand-held and have never had this issue before).

I also tried putting the camera on the deck railing and doing a "hands-off" video at 140mm, OIS on. Zero jitter. This is surprising, since the conventional wisdom is that for tripod shooting (the railing was a substitute for a tripod) the OIS should be off to keep the system from trying to compensate for non-existent vibration. But this video is crystal clear, absolutely stable and very sharp.

I had thought that maybe the jitter--which is very slight--was actually an artifact of line skipping in the video recording. But the zero jitter in the railing shot seems to rule that out.

I have done a lot of video shooting with the Panny 45-175mm* and the 100-300mm, and never encountered this problem.

*UPDATE: I did find very slight jitter in a one-minute stationary shot done with the 45-175mm about a year ago. It is now on a DVD; I never noticed it in many editing sessions, and no one ever commented on it. There is a lot of background motion to distract the eye; you probably would have to be looking for it to find it.

I wrote to Panasonic and got this canned non-response, which blames either the user or the camera:

"There are multiple settings for the stabilizer function with this camera. There is a stabilizer option for panning which users often times tend to neglect.  Nonetheless, you feedback is much appreciated and this issue has been brought to the attention of our research and development division."