I recently bought a Mavic 3 (used), and while everything seemed fine at purchase, it's been causing me some headaches.
The gimbal just won't stay properly level. And it doesn't just tilt in one direction, so manual calibration won't help, either. Instead, it seems to adhere to a tilted plane, which means in one direction it's level, but points down a bit, in the opposite direction it's also level, but points up a bit, and inbetween, it's tilted horizontally.
In some panoramas, this actually seems to cause issues with merging them properly, even when doing it in Photoshop.

I've tried doing a cold calibration of the IMU on a surface measured within 0.1° of perfectly level, followed by a gimbal calibration on the same surface, and a compass calibration before the next flight. This did not help, and resulted in the flight that yielded this footage:

I also took another 180° panorama, and it not only shows the issue, but how unpredictable it is. While this time, the assembled image ended up fine, you can check out the center image, the very left image, and the very right image below. You'll see that the center image is already a bit tilted, the left image is very tilted, but in the opposite direction, and the right image is pretty level:

Full Panorama

Center Image

Left Image

Right Image

I have, of course, already contaced DJI Support about the issue (just before writing this, so of course no response yet). But I'd love to know if anyone has any idea what might be causing this and how it could be fixed. Also, I'd be interested if anyone else is having similar issues or was having them but got them resolved.

Hi JustusLM, thank you for reaching out. May I know the firmware version for further confirmation, please? Thanks.

Hi, the aircraft firmware is 01.00.1100.

JustusLM Posted at 8-6 03:13
Hi, the aircraft firmware is 01.00.1100.

Thank you for your reply. For your issue, I forward to our engineer to further confirm. We will update you once we get the results, thanks.

Hi JustusLM, when the gimbal is warming up , maybe first couple minutes of the first flight, this could happen. I have it on mine as well. Once it warms up, it gets centered. It does not bother me as it quickly fixes itself once it is warm. Hope this helps. Take care, Mike.

Mzp Posted at 8-6 05:32
Hi JustusLM, when the gimbal is warming up , maybe first couple minutes of the first flight, this could happen. I have it on mine as well. Once it warms up, it gets centered. It does not bother me as it quickly fixes itself once it is warm. Hope this helps. Take care, Mike.

Thanks for your reply, but unfortunately, it doesn't help me as my issue appears to be different.

The following image was taken twelve and a half minutes into my second flight of that day, which followed immediately after a 29 minute flight (I checked the logs to be sure):

JustusLM Posted at 8-6 07:44
Thanks for your reply, but unfortunately, it doesn't help me as my issue appears to be different.

The following image was taken twelve and a half minutes into my second flight of that day, which followed immediately after a 29 minute flight (I checked the logs to be sure):

I see , got you JustusLM, must be a different issue, good luck with solving this soon.

Take care, Mikhail.

Hallo JustusLM,

Might it be just because of the high winds? I hike a lot in the mountains and also get this issue when flying but it happens because wind is almost always high in the mountains. You can do a test to check if it is straight when the drone sits turned on, using a leveled table and another test during flight in a room, to check if the lines are straight when flying perpendicular to a surface. My M3 Classic exhibits this behaviour only in windy situations, but not when doing these kind of tests or when there is no wind at all.

Tschüss!

iFlylikeafridge Posted at 8-7 13:27
Hallo JustusLM,

Might it be just because of the high winds? I hike a lot in the mountains and also get this issue when flying but it happens because wind is almost always high in the mountains. You can do a test to check if it is straight when the drone sits turned on, using a leveled table and another test during flight in a room, to check if the lines are straight when flying perpendicular to a surface. My M3 Classic exhibits this behaviour only in windy situations, but not when doing these kind of tests or when there is no wind at all.

I will test that, but the winds haven't been that strong a lot of times. Even in the YouTube video linked above, winds were below 5 m/s, the drone is rated for 12.

If it works properly in no wind at all that's nice to know, but still pretty useless if it doesn't work even in slight to moderate winds (this also hasn't been an issue with my Mavic 2 in similar wind).

Still, I will try it and report back. Getting more data about the issue can't hurt!

JustusLM Posted at 8-7 14:43
I will test that, but the winds haven't been that strong a lot of times. Even in the YouTube video linked above, winds were below 5 m/s, the drone is rated for 12.

If it works properly in no wind at all that's nice to know, but still pretty useless of it doesn't work even in slight to moderate winds (this also hasn't been an issue with my Mavic 2 in similar wind).

Hi JustusLM, sorry for the late response. May I know if the issue has been fixed?

Based on last conversation, we have forwarded the details for our engineer checking. Here are the feedback, thanks.

1. To judge whether the gimbal is skewed, you can compare it with the vertical line instead of the horizontal line, because when the angle of the drone is not parallel to the horizontal line, the horizon will appear to be non-parallel.
2. When shooting a panorama, the aircraft does not move, only the gimbal rotates to different positions for framing and final composition. Therefore, the original photos may not be level, which is normal.

Raise a ticket, add some footage and send it back. Mine had the same issue and turned out was a faulty Roll Axis Motor Module. The drone was replaced and there's now NO skewing...as it should be.  

DJI Thor Posted at 8-16 00:28
Hi JustusLM, sorry for the late response. May I know if the issue has been fixed?

Based on last conversation, we have forwarded the details for our engineer checking. Here are the feedback, thanks.

The issue has not yet been fixed. I also don't fully agree with the engineer's feedback, because a flat horizon is always perfectly horizontal if the gimbal is level (horizontal lines on, say, buildings aren't), and when shooting panoramas, the aircraft visibly yaws left and right – so it isn't just the gimbal that moves (also, shouldn't the left and right photos be tilted symmetrically?).

But regardless, from the support case I mentioned in my initial post, I got the recommendation to refresh the aircraft's firmware using the DJI Assistant. So, I did that, and yesterday, I tested it in little to no wind at all. And while it definitely did better without wind (although again – it should do fine up to 12 m/s), I also got this footage:


Note that the horizontal line stops moving nearly 16 seconds in, the remaining movement is all the gimbal.
The second clip is just a cropped version of the last seconds of the first clip, aligned so the vertical line is centered at the top of the stack (no footage or line was rotated).

There is quite notable tilt before the gimbal levels itself. The drone was flying at 10 m/s in virtually no wind at all, so it was far from being pushed to its limits. I had also been flying for 34 minutes at this point, so the gimbal wasn't  warming up anymore.

I'm guessing my next step is to create a repair case and send the drone in.

JustusLM Posted at 8-19 23:29
The issue has not yet been fixed. I also don't fully agree with the engineer's feedback, because a flat horizon is always perfectly horizontal if the gimbal is level (horizontal lines on, say, buildings aren't), and when shooting panoramas, the aircraft visibly yaws left and right – so it isn't just the gimbal that moves (also, shouldn't the left and right photos be tilted symmetrically?).

But regardless, from the support case I mentioned in my initial post, I got the recommendation to refresh the aircraft's firmware using the DJI Assistant. So, I did that, and yesterday, I tested it in little to no wind at all. And while it definitely did better without wind (although again – it should do fine up to 12 m/s), I also got this footage:

I see, sorry for the inconvenience caused. You could send back for comprehensive check to ensure your long-term usage. You could register through the following link, https://repair.dji.com/, to create a case and send back the device for diagnosis. If you need assistance while submitting, you could also contact with our support service, http://www.dji.com/support. Thanks.