QTR-Quadtone RIP

I'm making a curve for Entrada Fine Art Natural for UT7 ink on a 2200.
 When I print the calibration mode pattern page I get this mottled
look from the mid tones up to 100.  K is OK but all the lighter shades
have this almost camouflage pattern of light and dark spots.  Any idea
what would cause this?  I'm on a PC and nozzle checks are fine.

Thanks,

Tom