I don't think this leak could happen over night from a little acceleration. I floor mine everyday and its still running fine. If something it could of been from the frequent checks that caused this problem. If they unscrewed the same bolt over and over again they might have weakened it.
It happened to me with the bleed screw for the radiator when I did a coolant change. I had a hard time unscrewing it and when i put it back I didn't realize I weakened it. So after a little heat the screw exploded.
Just a thought
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Koni special active red, eibach pro-kit springs, Remus exhaust, stage 3 intake manifold,Stage 2 AA tune, BMW Short shift kit. Silicon intake pipe. M3 control arms front, M3 rear. ECS trailing arm with whiteline bushings. Purple powerflex subframe bushings. Yellow power flex upper shock mounts. Single mass flywheel OE weight.