QTR-Quadtone RIP

Hello,

Maybe someone had a similar experience and can point out what I might be doing wrong.

So basically I was trying to polish a gray curve for the silver paper profile I'm working on, when I noticed that the whites are slightly muddy on the final print. The same profile was working just fine the day before, but now all of the sudden I can't get pure highlights in my prints. As if black inks can't master enough density to block the light completely. Default ink limit in profile is 100%, and so is K density.
My first though was, something wrong with the chemistry, or the silver paper. So I placed a piece of black plastic over a portion of the negative, and that developed to pure white. 

So either something is wrong with the printer, or the profile. 
I keep exact records of every change I do to my profile, so I went back to the point where my stepwedge print showed pure highlights. Reprinted it with the same settings and got muddy whites again.
If anyone has any clue as to what else might be affecting highlights like that, please share.

The printer is 3880.  

Thank you.