Light leak? That's the problem, I'm pretty sure. Someone did the same thing to me -- loading up my sheet Tech Pan, gee it seems brighter in here, DAMN, hurry, finish up, lid on, sounded like Yosemite Sam when I come out.(posted 9152 days ago)I was using the dreaded Yankee tank, so the outer sheets on the rack were shot, but the inner sheets were printable but certainly not as nice as they should have been and lower in contrast (compared to properly loaded & developed film I did later). Don't let the slow speed fool you about light leaks. Additionally, there's a good deal less neutral density in Tech Pan's base than in most, which exacerbates the problem. Although that base is also responsible for one of Tech Pan's processing joys -- the delicious way it slides right on metal reels, especially after a few rolls of TMAX.
How thick are your negs? Are they faint (underexposure / underdevelopment)? Or are they just dull? I'm thinking they're "just dull" as your original post didn't distress about underexposure. If so, the light leak is a surer bet.
Of course, I'd have never thought to ask you about a light leak, or the content of your water, or possible rust contamination from an ancient tank, or if you fully mixed the Technidol / water solution, or if you carefully removed all of the coatings on a 15-element zoom before you shot the film with it straight into the sun, etc., all of which make me think that there could be an explanation tomorrow that will strike me as more likely. Good luck!