I don't have an answer. It appears to be similar to what I call a "magnetic" horizon tilt (yeah, I know. I just don't have a better name for it.)
On the two examples I have had, the camera was level when pointed north or south, tilted north when facing west, and tilted south when facing east. Both were on CG03 cameras. I spent very little time looking into it, because both fixed themselves while I was trying to study them. That is obviously not going to happen here, since the condition has existed for more than a year.
I looked through some old threads. The only "home remedy" that was recommended with any apparent confidence was on a TH / CGo3+ combination. The recommended solution was to create a new model and run new "calibrations". The article did not specify which calibrations. There was no feedback to report whether the method worked or not. (Another article reported that it did not help.) At least it's easy enough to try. And would provide some value if the results were reported, either good or bad.
Another member reported the issue cleared when he found and repaired a stuck PWM contact on the camera mount.
A couple folks mentioned the problem went away after removing camera, restarting, etc.
Some folks reported the issue appeared after installing updates.
I am not even sure the cause. Prime suspect would be the IMU, but that is just a guess.
It would be great if someone could team up and try different combinations of camera/ drone /controller.
And, as
@Panther6834 has mentioned, there is always Customer Service / Repair Center. Might take a little time, might be a little expensive, you will never know what caused it or cured it, but it does have the advantage that the camera will probably work again.