Digital BW, The Print

I need some help on an issue that is stumping me. Epson 9000, Cone 
selenium quad inkset, ImagePrint 5 RIP for Windows, photo rag paper. I 
am printing some portraits for a client and I am getting a weird white 
line (no more then a pixel or two wide) that encircles  the pupil of 
each eye. Actually it only goes half way around the bottom of the pupil 
if I print with the orientation in the printer looking upright and 
correct. If I rotate the image it will now shift to the side of the 
pupil, so I am sure it is not in the file. I have done nozzle checks 
(perfect), done head alignment (all were in the middle numbers), tried 
different profiles, tried blurring the image a little, and it will not 
go away. It happens only on certain images so it might have something 
to do with a contrast ratio or out of gamut (if that is possible with a 
grayscale image) but I am completely stumped. I am now wondering if it 
is another more serious alignment issue and should I do the skew, etc.?

Any guesses? I apologize for cross posting this but I want the most 
feedback (help) I can get.

Thanks to all,
Mark