Cymk black is brown on screen

I have a client that is using InDesign to create cymk documents and suddenly any pure  black items show as a dark brown.  It is especially noticeable when  bringing in a grayscale (grayscale color option in Photoshop) images to place them on a black background.  The image being placed has black and it shows as true black on the screen but the box that the image is placed on created in cymk is brown.  Basically if we use rgb for the indesign document black is really black.  When we export to pdf or print to a black and white printer the brown turns to a very dark gray and the black of the placed grayscale image stays black.  We spent an hour on the phone with Adobe and they could not find a solution other than to have us use rgb for everything.  This is not an option though because the client is a newspaper and the company that prints the paper for them requires everything to be in cymk.  When the newspaper gets printed by the printing company the results are the same as exporting to pdf (the brown that is supposed to be black turns to dark gray and grayscale black placed images remain true black).

One other note, we experience the same problem on the other design PC (I will call that one graphics pc2).  The other PC is a totally different model of PC than graphics pc1 but it has the same model monitor.  We tried it on one other PC in the office (I will call that one admin pc) and it does not have that issue, all blacks are truly black on screen.  Admin PC is the same model of computer as graphics pc2 but has a different brand of monitor.  The two graphics PC's are both using displayport connections for the monitor, admin PC is using VGA port.  But even with the difference in monitors and computer models that doesn't explain why the color is off with printing.  I could see if it were only happening on the screen, but it happens when printing from any computer.