How are you measuring temperature? Is this a setting on the dryer? On both dryers? If you are using a probe like an Atkins Donut, I'm stumped, but without a reading of the bottom of the ink deposit itself, it can't be right on. However, with most 50/50 Navy and low bleed (or as you said poly specific) inks, you should still have a little wiggle room.
At any rate, crappy offshore dying quality control notwithstanding, I'm betting that your ink is indeed getting hotter than 325, and it is not merely because it is now gas, but rather that the 325 setting or reading is merely inaccurate for the actual ink temp.
