I've only ever seen spokes break in the middle when there's already some damage there, like something scratched/etched them creating a stress riser. Otherwise that's not a fail point. If there's no visible damage, check the broken spoke and the rest on the same side, I would assume maybe a bad batch of spokes that were drawn out improperly creating the problem. Based on the cost of any future fixes and the cheapness of the wheel, I'd just replace it rather than do another fix, should be 75-80 for a basic wheel like that and the problem is gone. I've always had a 3 spoke replacement policy, on the third break replace or rebuild, but with the weird location I'd be inclined to skip a break.