If you have that lens you should contact Panasonic service. We may have a FW fix if many people complains.
I have heard that Panasonic knows the issue but I am not sure if they are doing something.
I have tested 2 copies of that lens with 3 bodies (GH3,GH4) and the OIS vibration is exactly the same.
If you have not noticed that OIS vibration try shooting a stationary hand held shot at 14mm and see if image jitters or vibrates.
I have heard that Panasonic knows the issue but I am not sure if they are doing something.
I have tested 2 copies of that lens with 3 bodies (GH3,GH4) and the OIS vibration is exactly the same.
If you have not noticed that OIS vibration try shooting a stationary hand held shot at 14mm and see if image jitters or vibrates.