I have a problem with my Rockomax Jumbo-64 Fuel Tank and an adapter, which I tried only because the coupler failed. I went so far as to put ab 12 to 18 struts trying to hold it in place. It happens within the first 5000 meters. It also happens on both of my couplers/adapters. the adapter helped, though, it still happens. All parts are the same size so an adapter doesn't actually fully connect. Sorry if I am not describing this very well, it is late and I am tired.