What difference does it make? It's 100%k and that's what you want.
What's the issue here?
I think you'd be better of checking Acrobat Pro's own Advanced>Print Production>Output Preview for colour breakdowns.
First, Thanks a lot for the answer, Eugene.
Well, for most users it's not a problem, I think, because only a few print companies choose to reconvert the incoming PDF's colors in their Color Management flow.
In my company's case, though, the "Separation: Black (Process Color)" results in a 4-colored text many times, especialy when the text is over a colored background. That's the issue.
It's Agfa Apogee Workflow Software's fault, since its algorithm can't understand the case as we do (i's 100%K and period).
If I could understand why it happens and when, maybe I could prevent it from happening.
Per PostScript and PDF specifications, Separation Black should be treated exactly as DeviceCMYK=(0,0,0,K). It your Apogee workflow software is not treating it as such and is actually creating an extra separation, complain to Agfa. They are grossly “out of spec.”