This is a series of shots taken in the same location, with the same setting and within 6 minutes of each other. The camera, however, registered the colors differently. I'm wondering if anyone sees any clue as to what would cause the different colors. From top, left to right, they were taken at 9:48, 9:50, 9:53 and 9:54.

Nikon D750 With Sigma 14mm lens at F1.8 for 30 seconds ISO 4000

Created collage in Photoshop