Reads as CMYK but is Gray

[jeffkr@adobeforums.com]

I received a PDF, opened it in Acrobat 6.0 and checked the Separations Preview, and although it appeared all gray, there were values showing on all CMYK plates. Now, when I used the Touch Up Object Tool, and opened it in Photoshop CS, the image came up as a Grayscale image (not CMYK), all data was registering on the gray plate.
Can anyone explain what might be causing this discrepancy?
Also, Pitstop reads the PDF as a Gray image?

[Aandi_Inston@adobeforums.com]

Maybe it IS a grey image but you have selected color management
options which cause grey to be separated onto all plates.

Aandi Inston