How do I disable weird lockscreen camera shortcut in Emotion UI 4? Device: Huawei Mate 8 EU (NXT-L29), EMUI 4.

When my phone is locked and I press volume down or up quickly, camera app opens, takes a photo and displays on the screen a time I don't know the meaning of (like 1.0s or 0.3s). I have searched through all settings but I still can't find this feature. When I listen to music this is VERY annoying: lowering or increasing the volume with the keys causes a photo to be taken. It happens both when the screen is off and on in the lockscreen, but never when the phone is unlocked.

Also before rooting my phone I did a factory reset (which now I can't do), and it didn't change anything, of course.
Found it! In Huawei Camera, in the settings, there is a feature called "Ultra Snapshot", which by default is turned on, and it does what I have described in the question.