I have noticed recently that that my 42 is consistantly more difficult to lock open after manipulating it. I like to go from normal manipulation to pivots seamlesly, but it requires some serious force to push the handels together enough to get it locked. But, if i have been doin pivots, onlock it, then try to lock it again, it's easy. So basically only after swingin' it around for a while...any idea's?