After posting this I realized that I had a few sheets of the Feb. stock still loaded in holders. I pulled one out, ran the same test and it matched my previous February test so close the curves overlap. I was recently on an extended photo trip and thus kept meticulous notes about film loading/unloading that allowed me to figure out that I still had the older film in a holder that never got used so I am pretty sure of this at this point.

So my newer box of 100TMX from July is definitely the culprit here. For whatever reason the newer film I have develops much thinner than the previous box. Maybe it's older or a bad batch or was mishandled before I got it. Maybe something has changed with newer batches, I really don't know at this point. The two boxes were bought from different suppliers, the good one from Feb. came from the View Camera Store and the off-box from July one was bought locally in Seattle from a pro suppler. Both were kept refrigerated as far as I know. They are different batches though as they have different codes on the boxes. I have no idea which one is older stock.

For reference, the odd behaving box has this code on the box: 02GJ0H. I wrote Kodak pro support so if I hear anything I will update this post.