I have had nice results in the past shooting Kentmere film and processing in both HC-110 and PMK Pyro. Recently, though, my negatives end up looking a stop or two underexposed. I bought a new beaker and a syringe for measuring and mixing the developer, thinking that the problem could be contamination of the processing equipment. That made no difference in the outcome, however. I still had to compensate for the thin negatives with Photoshop adjustments. So, my plan now is to shoot the film at a stop slower and accept that it is not going to produce what I want at the rated box speed.
It is tempting to theorize some manufacturing fault, but I haven't seen any reports on the issue elsewhere , including from the people who have inspired me to use the film at Photonet and Rangefinder Forum. On the up side, the fact that I can get a reasonable outcome from the weak negatives speaks to the fundamental excellence of the film in regard to exposure latitude and fine grain.