Again:
Have you recently performed either Compass or Accelerometer calibrations with the camera mounted but not secured by the gimbal lock?
This is an important question. The C23 is vulnerable to ribbon damage from unrestricted gimbal movements. Calibrations are a common source, as is transporting the camera without the gimbal lock, hard landings and crashes. And some fail with no apparent reason. Your symptoms suggest a possible damaged or degraded main ribbon. There are other possibilities, but discussing the ribbon is usually a good place to start.