I have seen and faught this same scenario. See if your cartop inductor wires are shielded. If they arent then splice a shielded set of wires to the original ones at the inductor and ground the shield in the COP. This completely fixed my problem and its been going for just over a year now with no reoccurence.
Also if you havent changed the modules, try that.
If the unit uses hoistway switches for this funcion then check to make sure the spring plate that reutrns the switch to the normal state isnt cracked causing the actuator to rock back and forth after the cam moves away from it.
These are all things I've found in the past and just recently that can cause this fault.
