Inconsistent lighting in interval mode?

[Inoxx]

Hi all,
I'm shooting photos in interval mode to make a timelapse with the M2Pro, latest firmware. I'm using manual settings: Aperture, shutter, ISO and manual white balance. I'm still getting some brightness compensation as the scene gets darker (shooting sunset). As far as I can tell everything is identical in the exif but I'm still getting brightness jumps as if I was shooting auto. Any ideas?
I'm also getting a lot of green/purple hue shifts from frame to frame.

 

[Kilrah]

Almost every camera will have small variations even in manual that will be visible when doing timelapse shooting, that's why the various processing programs that are used to make a video out of the stills have equalization algorithms.