Fresh Start primer is one of Moore's best primers, but it's intended purpose is for priming over existing paint when surface integrity is in question. I still have to stick to my guns on the odor not coming from the ProBlocker. I assume that you've done the final coat of paint? Could it be that your finish coat of paint is the problem? Open the can and take a wiff, each brand of paint has it's own smell, but if it has gone bad, you should smell that "Sewage" smell. If that's the problem, I'd use KILZ or CoverStain to seal the odor in and repaint.
Just for your info, there are some really great paints meant for bathrooms that will not mildew and provided the previous finish is sound, resist pealing as well. PermaWhite (Can be tinted) is manufactured by Zinnser (Makers of BIN and CoverStain) and Benjamin Moore has sone they call Kitchen and Bath paint. Sherwin-Williams has one as well, they're all good. They all have a satin sheen to them which will show defects in your walls.
Sorry, other than repainting, I'm not certain what else you could do.