Both an Extralite Hyperstem which only torques to 3NM at recommendation and a 3T Arx Pro II which I didn't get past 2NM before the bars crimped. Perhaps I was just unlucky, as I ran a set of Rotundo LTD for an entire summer of up and down mountains in Switzerland without any issues.
Interesting. Not had my 3Ts crush at the clamp, slightly over-tightened them too. What stem are you punishing them with?