those shiny drive bones (part numbers sb 016) on the end axle shaft where mine broke was made out of pot or cast metal. Yes it broke at the drive pin location. What I noticed right away is the drive pin hole wasn't round like the pin it was oval shaped. Looking at this I saw there wasn't much meat on the axle shaft to made it strong. No amount of hex adapter modifying is going to fix an inferior axle shaft. I can see those continuing to break until someone MIP, academy, whoever makes an all aluminum cvd and axle shaft.
Since I dont see this in the near future I will run the cheap stock black steel 2 piece dogbone and steel axle shaft all around the car. I know i know those wont break like the sb016.
Something else to consider is that if you didn't want to run the academy rims you may be able to pull the hex adapters off and try fitting (I'll try tommorrow) XX4 , proline or asscoiated rims on the sport-All depends on the thickness of the rim and the length of the axle shafts.
removing the hexs might eliminate the problem.