I have found that the issue was not the film. I retraced by daybook and found that I shot both rolls with a Minolta A9000. I still have the rolls of TriX shot with the X900 and Chinon point and shoot waiting to be developed. If only I kept the rolls together I would have developed all 4 in my Unicolor film drum. I have 3 9000 bodies, one died with similar issues. Minolta like Canon EOS AF move to a lens mount that skips the aperture ring, all aperture functions are controlled by the camera. What happens is that the chip that controls the aperture fails in a very odd way, regardless of what I set, or for that the camera set while A or P mode the lens stops down depending on the lens to F16 or 22. When my first 9000 failed it failed all at once, in this case first 10 frames or so are good, then 8 to 10 underexposed by 3 or 4 stops, then remainder of the roll looks to be just fine. I cleaned the pins and lens lens connectors and set the camera on 1 second ran the aperture from 1.7 to 16 on with a 50mm lens, 22 dry fires later and still good. Maybe just a dirty connector or perhaps because of the heat, it was 98 degrees when I shot those rolls at the local zoo. I also checked the lens I used on a Sony D body, no issues. I have bulk loaded film from only God knows where that I use for my walking around film. This weekend I will run a roll though the A9000 to see if I can replicate the issue.
Sorry for posting before I had figured what had really happened.
