I'm flying a GH4 and a light lens (Olympus 12/2.0) on my ALTA with a MōVI M5, not the M10. I wonder if the GH4 is too light for the M10? Have you considered adding some weight and seeing if that helps (after you rebalance and retune the M10)? You also might want to mount a GoPro on the ALTA first, then on the MōVI to see if you can determine where the vibrations are coming from. Do you have any dings or issues with your props? One prop with a problem could conceivably cause this kind of problem in my experience.