Strange printer profile

[jstotz]

I'm trying to build a printer profile for an HPZ2100 using a matte proofing paper. (I'd rather not say which RIP I'm using because I'm still working with the vendor's tech support.) After going through the linearization process, I run an IT8 target with no calibration. There are some areas of the IT8 target that don't look right. The 2 color ramps in red and green are much more saturated than the neighboring 2color+k ramps. When I build a profile with Profilemaker using the default inkjet settings and view it with the 3D profile viewer, I get some strange overhangs. (See attachments) In 2D these look like separate detached islands at some L levels. If I use the max black setting in Profilemaker the profile looks somewhat better.

So my questions are:

Does this sound like something anyone has seen before? Is it typical for a printer profile?

Does this sound like a problem with the linearization process?

Why does the choice of separation settings change the look of the printer's gamut in the the 3D view?

Thanks