Rattling Pen EP5

I bought the ep5 a couple of months back. Very pleased with the results. However, I have noticed that when the camera is powered off there is a definite rattling sound when the camera is moved. This is noticeable when the camera is worn across the body and walking over rough ground. Searching on the forums and a bit of playing with the camera this definitely seems to be the sensor moving around the axes of image stabilisation. First question - have others noticed this to a significant extent? Secondly - I plan to off-road bike tour with the camera. My concern is that the sensor and/or stabilising mechanism will fret and be damaged with extended bumping up and down in a pannier. Anyone have experience of this?