Had exactly that happen to mine too, and I was using a torque wrench on their settings.I tried to put mine on today and had a bolt sheer in the U bracket. It was not tight yet either. It was not as easy as the others to get in though. Both sides of it were tough for both bolts i tried. Thinking a manufacturing flaw like the part was not alligned when the holes were tapped. I am hoping I can get a replacement from yoshi. both the bolt and the U bracket are useless now.
Used to working with many CnC parts and know that sometimes things can be off if the part moves or is not alligned right when you tap the holes.
I emailed yoshmura directly, but if that fails, i will be returning the whole kit to where i bought it. I too was using a torque wrench on their settings.Had exactly that happen to mine too, and I was using a torque wrench on their settings.
Be interested to know how you get on with replacement parts as my dealer said he couldn't get.
They finally came in today, these attach directly to the frame and require no cutting! Also at a beautiful price of $180 per pair from a reputable brand.
As soon as it stops raining here, I will get these on the bike and snap more pics.