I've started having trouble with my gimbal and am hoping there's an easy fix, rather than having to send it back to DJI.  When banking, the gimbal fails to keep the image level, so a tilt shows in the shot, which gently levels after a few seconds.  
Using the latest FW.  
I've not forgotten to remove the gimbal lock.
I've tried calibrating the gimbal, but that's not helped.  
Here's a video showing the problem (which appears about 10 seconds in)...

I think you probably need to have a play with your Gimbal gain settings in the app.

It looks like to me from your vid the gimbal is over compensating when you bank etc.

Settings are explained in this video if you are unsure:

Had a lot of gimbal tilts when got mine. I've since got the IMU and gimbal figured out. You want to make sure the ac is cold and do the imu calibration on a level surface and get it done before the ac fan kicks on. Make sure there's no vibrations like people running if done on the floor. Shut it down and then do the gimbal calibration on the same surface. Key is to do them together on the same surface and the if the fan kicks on during IMU calibration, cool the ac back down and do it again.

I know some don't like the refridgerator but it works. Put it in a bag so no moisture gets in. Leave it in the fridge for 30 minutes. Have the controller, go app on, and level surface ready. When you pull it out of the fridge, make sure you know the IMU procedure, get it done fast. The ac fan (rc also has a cooling fan, but that doesn't matter) should not kick on during the calibration. No vibrations either. That did it for me.

Then outside, you want to check horizon and make gimbal adjustments to level. gl it works

http://bit.ly/2pip6LK

Some raw footage from a friends farm. You can see the gimbal stays level even in poi. He flew the second part, that's not me xd

You aren't the first..

http://forum.dji.com/thread-86729-1-1.html

Thanks for all these comments and suggestions. I'll be working through them to see if there's an improvement.  SnowBirdL, I had a look at the other thread as well.  I'm interested in the suggestion that turning "off" "Enable Synchronized Gimbal Pan Follow" could help, but no one followed up on that suggestion in the thread.  I'll look into whether that helps as well.

GMG Posted at 2017-4-10 23:36
Thanks for all these comments and suggestions. I'll be working through them to see if there's an improvement.  SnowBirdL, I had a look at the other thread as well.  I'm interested in the suggestion that turning "off" "Enable Synchronized Gimbal Pan Follow" could help, but no one followed up on that suggestion in the thread.  I'll look into whether that helps as well.

yes turn off "enable synchronized gimbal pan follow" definitely solve the horizon tilt issue when i own the phantom 3. so the trick still works on mavic, too. the side effects is you can not do the camera maneuver smoothly.

fans915ed907 Posted at 2017-4-11 00:53
yes turn off "enable synchronized gimbal pan follow" definitely solve the horizon tilt issue when i own the phantom 3. so the trick still works on mavic, too. the side effects is you can not do the camera maneuver smoothly.

Hmm.  Will have to have a look as that may mean that the side effects that come with the cure are worse than the illness.