I remember seeing this story (or one like it). There is a guy who runs a company that finds lost pets and people. I think they said he had FLIR mounted on a drone to locate heat signatures....very cool.
I repair a lot of DJI drones. The signal cable can look fine but be bad. Generally, if there was any stress to the gimbal, in your case, the broken yaw arm, it is reasonable to suspect a bad signal ptz cable. Im assuming you replaced the yaw...