Good investigative work.
My jet was talking to me yesterday. One of my flaps was not operating smoothly as it normally would. I removed the wing and plugged in a servo tester. All is good, servo worked excellent. Decided not to fly and took it home. I pulled the servo extension wire out of the fuselage and found the signal wire was barely attached. I installed a new extension and it is back to working like a champ.
I try to always listen to my instincts and have missed out on some great flying days. Better to be sure than chance something.
Jeff