I only notice this yellow shade after creating a HDR (Near the top of the building in the foreground. The image in this question is cropped from the oirginal)
I didn't notice before because HDR makes it stand out.
Here is the original 0 ev image
I have checked other images capture by the same camera and I did not see the same yellow stain. I can rule out it is a hardware issue.
I want to learn how this artefact happens? I am not pointing into the Sun directly or in its general direction.
If it is not easy to spot on a monitor, I will definitely miss it on the LCD display of my camera. Understanding how it happens can help me to avoid taking photo I might find useless in the future.
The photos were captured in the morning around 7:26am local time.