What you describe apears to be the result of what is called infectious development, caused by halation or the scattering of light in the film emulsion. You typically see this in the shadow areas adjacent to extreme highlights. All staining developers, including PMK and Pyrocat-HD, tan and harden the gelatin, and minimize this effect. Assuming your original negative was developed in PMK I don't believe another staining developer would do much better.
It may also be that the negative was simply developed for too long. This would accentuate the bleed over of density from the highlights into the shadows.