Based on my multiple experiences with sheared axles

it doesn't make any difference which way the dropout is oriented.
The most likely cause of this type of shearing is one of the axles being not *completely* immobilized, so that it can rock back and forth, even just a tiny bit, while the other *is* immobilized, and cannot move.
The axle that cannot move would be more stressed than the one that can, and would be the most likely to break at the stress riser of the axle shoulder.
This is what I've seen on my SB Cruiser trike, whenever I've broken axles on any motor--the end that breaks is the fully-secured one, and I can feel the rocking of the other end, after the break disconnects the fixed end from it.
However...it could also be a specific problem to some of the QS205 axles; I've seen this problem posted more than once, and I have one here (from Shortcircuit911) with *both* axles sheared off at the shoulder (though this one was more likely because of *both* dropouts being loosened as the axle worked the metal of the dropouts over time). It is, however, more likely in cases like that, where much higher power was being used than the motor is sold as rated for, that the problem is in the amount of torque placed on the axle, which was not designed for that much torque.
The latter shouldn't be the case for this thread, as the