One for the brains trust and petermac33

I would be open to suggestions to explain this photograph.
Yesterday 16th of June 2020 @ 10.46am Facing the west I took a couple of photographs of a rainbow. Both photo's were taken seconds apart, from the same location with the same camera as verified by file. I have just down loaded and noticed a slight difference in the images.
Image A. DSCN6604.

Image B DSCN 6605

Those with sharp eyes may have noticed almost in the centre of the arc on image A there is what appears to be a white line originating from the spectrum, it appears to originate in the arc and from this perspective point down, this line does not appear on image B, nor was it visible through the lens when the shot was taken.
Below is the cropped and enhanced section of image A.

Now I am not an expert on imaginary interpretation and have really no idea what it is, had it been on the lens it should have shown on both shots, I think it is something natural but I'm curious, any ideas?