Or some loads were different from the ones expected. As this AD shows, there can be a problem with the two (or more) actuators attached to a control surface which can "fight" against each other, resulting in high loads between those leading to premature fatigue failure of the actuator attach fittings. For "traditional" aircraft this can result from misadjusted control linkages, stiff or seized spring rods, wrong wire tension etc. For "modern" FBW aircraft the actuators are electronically commanded, there could be a rare (and undetected) failure cases that result in two actuators fighting against each other. This could be a good explanation for such "one of" fatigue failure of an actuator fitting. The loads on an aileron of a long range aircraft (basically zero for most of the flight) compared to the loads actuators could produce against each other are extremely different. You do design such fittings for the static loads of such failure cases to "get home" and repair, but not for fatigue
Hmm, sounds like the B747 Pylon to wing attachment and El Al (Netherlands)