dude. i experienced the exact same prob on my set of pauls --split locknut. i don't use a torque wrench, but do crank them down pretty tight --like yourself. i had a problem with the rear sliding in the drop-out, end eventually had to throw a tug-nut on the drive-side bolt (this didn't solve the slide issues, but did help some). i contacted paul directly, and although i didn't think to ask him how frequently this problem occurs, i gathered by the tone of his response that it's a really common thing. to his credit, he did his best to make good on things and sent me a gang of new nuts... i've had some bearing issues, also on the rear hub as well. i am certain they are related to over-tightening. all is all, although i'm pretty stoked on the pauls, they feel a little more delicate than the phils i have.