The original firmware for the Alcatel IDOL 4 Pro had the software 'wiring' wrong for the top and bottom microphones on the device, such that when you video-ed something, left was right and right was left. Not an issue most of the time, but when cars, people or pets are moving across the field of view then the result can be strange, to say the least.
So as I say, in lieu of Alcatel fixing the issue at the heart of the IDOL 4 Pro (and IDOL 4S in the USA), Microsoft took the line of least resistance and simply fixed it in software. Windows 10 Camera now switches the audio channels at capture time if it detects that you're using an Alcatel IDOL 4 Pro. So, effectively, left and right are wrongly swapped by the phone and then swapped back by the updated version of Camera!
(You can verify that the firmware itself is still the issue by running one of the many audio recording applications for the platform and you'll see that the channels are still inverted.)
Just as proof, I shot a quick bit of video with traffic moving from side to side:
Any comments? Had you even noticed that this problem existed?
[Update: see the comments below. It seems operation is still inconsistent. Oh well. Back to my Lumias!!!]