I doubt that the accidental drops were caused by faulty guidance. Those bombs have attachment rings that are used by the drop mechanisms to hold the bomb under the wing.
Those rings were designed for the bomb, but not for the bomb and a set of added on guidance wings folded up underneath them. Adding weight and causing air turbulence while the aircraft is in the air. I'm pretty sure that the wings under the bomb cause it to be yanked around by the air it is passing through at high speed.
My guess if either the mounting rings on the bombs are breaking, or the hook release mechanism in the pylon which hook onto the bombs rings are breaking under too much load.