[xoxoxoBruce]

No, any position. It can be affected buy using the off hand to support it by holding the head, but we're talking maybe a ft lb or two, nothing critical in most applications. It could be a wrench malfunction, but I'd be more inclined to suspect the bolt was defective or had been damaged somewhere along the line. At some point it might have been over torqued.

When a bolt is tightened first it stretches. On steam chest bolts we'd measure how much the cover bolts stretched until it reached a predetermined length, because it was too difficult to measure torque accurately on six inch diameter bolts.

Next the bolt reaches it's yield point. At the yield point the weakest section of the bolt stretches a little as it relieves some of the built up tension. That stretching(yielding), causes that point to grow slightly smaller in diameter. The manufacturers use some torque-to-yield bolts these days, hence bolts which can't be reused. The manuals identify those.

After it reaches the yield point, if you keep twisting, that weak point is where it will snap.