I had the same problem 4-5 times i also replaced bolts with higher grades and they sheared as well.
last time it happened is 3 weeks ago when i went off road.
I talked to keith from twisted throttle.
I reinstalled the whole thing again new spacers ,bolts etc... we will see what happens.
last NEVA I left with my rear rack zip tied and strapped ,i hope this year is different .
if it isn't i will have a more serious talk with them,their customer service is usually very good so i don't anticipate a problem
2014 vee2- OEM:skid plate,heated grips,mirror extenders,centerstand. aftermarket:sw-motech: risers,trax 45L side cases 38L top case,pipe valve guard, kickstand foot enlarger. corbin/holshot heated seat ,MRA VarioTouringScreen,burkbusters storm,PC8, kaoko throttle lock, scorpion titanium slip-on, denali airbomb,scottoiler,denalli dx.pc5+autotune R&G:radiator guard, pipe slider K&N:air filter touratech:crashbars, ABS kill switch,dryspec tool tube,cyclops LED headlights,doubleback mirrors,helmet guardian,twowheels shorty levers,aftermarket off road rear brake lever,shorai lithium battery.