After receiving my C23 replacement (you can read more about my case here), I've performed a small flight test this weekend on my birthplace.
The way C23 captures detail - especially on low-light conditions - makes it my favourite
I've noticed it too, probably had to do because I've launched from a terrace that is not flat (has about 5 degrees tilt in order to drain water).
The Typhoon H+ does not have any camera calibration box or gimbal calibration menu.
I've sent an e-mail to Yuneec Europe asking if there are any procedures (or an external tool) that allows gimbal calibration on the C23.
I suspect that there might be some service-approved tool to calibrate the horizon regardless of the automatic power-on calibration.
The Yuneec Europe technician - the same one that replaced my C23 camera - replied to my e-mail telling me to perform a compass calibration with the new camera attached to the drone. According to what he said on the e-mail, the C23 gimbal IMU levelling is performed when doing compass calibration and this means that the C23 must be attached to the Typhoon H+ while doing the calibration. I always perform compass calibration without the C23 attached to the drone in order to minimize stress on the gimbal motors while turning the drone; the technician told me to NOT perform the calibration without the C23 attached and to not worry about the gimbal motors going "crazy" during calibration.
Guess I have to take the Typhoon H+ again with me this weekend to perform the calibration on Lagada's football field.
It might be true because the C23 camera that came with my H+ had a perfect level right out of the box (it came with firmware build 652) and the first time I've calibrated the compass was on firmware 822 (almost two years since I bought the drone). The reason I did the compass calibration was to check if it affected the jello that appeared on video (as explained here), otherwise my H+ flew perfectly without ever performing a single calibration, which is even more amazing because the drone came all the way from Germany to Greece and did not required it. On the other hand, my dji Mavic 2 needs most of the time compass calibration, even when moving 15km from the last flight location.
Will post more information when I do testing this weekend.