For this to be an issue with the clamps, both of them on one arm would have to have come loose. If only one came loose the barrel wouldn't have been able to rotate and adjust the toe.
My gut says you're not running the eccentric lockout plate and that slipped? If it was actually both clamps on one arm, I'd bet a lot that they weren't tightened properly after the alignment.
__________________
Light travels faster than sound, so people may appear to be bright until you hear them speak...
flickr
|