They appear to have been over torqued. Just because you can still crank on a nut, does not make it right. Thread stretch is an important part of the equation, thus the reason there are limits and requirements on Tolerances. I suspect the reason for the bolted U Clamp was/is to hold it in place. Have the installer go a little less on this with the impact wrench, as they are not the same tolerances as Wheel Studs. I have struggled many times to remove a lug nut because some monkey got a little nuts with the impact wrench. Thus creating a weak fatigue that over time fails.
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