Zaid not familiar with the vibration mount that you show. Is made to handle the weights involved? Can you change to different strength rubber isolators? It sounded like you have two isolation points but I don't see that in the photos. Others have found that they have a whole new set of problems with a double systems as Steve points out. What happens if you direct mount the MoVI to the bottom plate without the Toad? Also any flexing of motor booms, out of balance motors or props can contribute. And hovering flight is just about the worst situation since the copter is sitting in disturbed air.