I've been watching this Dupe for quite a while, and the "Minor Irritation" debuff has been sitting at 0 seconds without disappearing, even when sitting in gasses that decrease irritation for prolonged periods.
At least at this point, the debuff itself doesn't seem to carry an attribute penalty... but it's still a warning on the Dupe's status, and the Dupe still stops to rub its eyes every so often, which definitely is a debuff.
While the Dupe has wandered around a lot, the debuff is still there... 5 cycles later.
In this image, all of the gas tiles are either Oxygen or Carbon Dioxide. Low pressure, to be sure... but still, both gasses are supposed to "decrease irritation."
I've attached the save. I don't really know how to repro it, and there's a chance that it may auto-clear on load of the save. On the off-chance it doesn't... just look for Nails.
It happened with zero effort on my part during the early game; I have yet to establish a pure Oxygen atmosphere in my base, so it was probably pretty mixed at the time.
- Poor Nails has suffered from a lot of hypothermia, as Nails is my primary digger/builder. I wonder if there's a chance of an interaction between the two effects? This has only been a problem for this one Dupe so far.
- A random thought: the test would be a pain to set up, but... what if both Hypothermia and Minor Irritation were both supposed to clear on the same tick?