Is this a basement area? Did you prime prior to painting? What manufacturer of paint did you use?

This is my living room and entryway. It is on the first floor of my house and dampness is not a problem. I live in California and we're in a 7 year drought. We cleaned, scraped and primed before applying the new colors.

It is Benjamin Moore.

Very strange. My only thought is that the paint is defective. Was it mixed to order or did you purchase off a shelf? Which manufacturer did you use? How long was it before it started changing colour? If you primed then you sealed the drywall properly. Sometimes previous wall colours can bleed thru when not primed. I am a huge fan of Benjamin Moore. I have never seen this issue before.

I would contact Benjamin Moore and explain your situation. It could be the way the paint was mixed and defective. Their technical advisers should help you. If the paint is defective then they should replace it.

Have you changed the lighting in the room? Light and shadow can give the illusion of distinct color changes. I was certain that our painter had used two different colors on a foyer wall when In reality the color change was created by a shadow from an adjoining wall.

Lighting is the same.

http://terrylove.com/forums/index.php?threads/drywall-seams-showing-through-primer.17069/

This article seems to indicate that primer and paint was applied over mudded drywall seams to soon.

The drywall was not new on all of the walls of my home. However the discoloration occurs everywhere the two gray colors were applied. Both grays were from the same line of paint. The walls which were painted white or from a different color family do not show discoloration.