That said, people on Discord were confused and unsure. I asked MaRo, so I'll notify you if there is any updates.
If 2 damage is corruption and 18 damage is regular damage (assuming no healing) you lose. It works together with damage, it's not a parasitic thing like poison. Granted healing mitigates it, to a degree.
uncommon - Thopter's arrest and it's uncommon probably because the text was 4+ lines).