When I first read this, my initial thought was, she got her photos back and now doesn't like them...
Today digital photography is so different and manipulated so much that the colors can be so different from what is real...many photographers are artists in their own right and manipulate the photos alot and color correct even do funky things to the colors in the eyes of art, others not so much...what she is seeing in her photos may just be the photograohers vision of how the colors should look..I have noticed when retouching my own photos, that the colors of flowers can change drastically when changing the contrast, shadow and highlights...
I would have a objective conversation with her and try to cajole the reasons why it took so long for her to dislike the colors, you may just get her to say that the photos don't look good and then that is your out...I have found that when I am rather confused by a complaint because I didn't think there was any kind of a problem, most of the time when talking with the customer, I can get to the bottom of the real issue just by haveing a very quiet and adult converstaion and listen to them about their problem...when you hear things come up that have nothing to do with you, you know you really aren't the problem, you are just getting the crap end of the stick!