Hmm, was thinking of Shad too where my givi sideboxes malfuctioned during high speed bumps, one fell off the bike and the other popped open. Givi topbox too has been known to take off. Overloaded and huge impact shock makes Givi a flyboy.

Did the box ever try to shake the bike's tail at high speed?

Givi or any boxes are know to fell off the rack, I suspect of heavy loads. When you hit a bump or slammed the bike hard enough they might fly off that bracket so put things lightly. I've had couple of times my sideboxes popped open or fell off because of weight. The tell tale sign is the loose fit when the box is locked in place. There may be temporary fix but as it wear off the problems come again.