Kronging Plague Doctor's Mask never gives any stats. The kronging text seems to be ok though. Same thing applies to getting this item as a monster zoo reward.
There's a couple items like that for some weird reason. They'll be changed if we ever do another pass at the items.
HTML: <item name="Plague Doctor's Mask" iconFile="items/helm_plague_doctor.png" artifact="1" > <price amount="1250"/> <armour level="6" type="head"/> <secondarybuff id="10" amount="1"/> <!-- armour --> <secondarybuff id="7" amount="3"/> <!-- block --> <secondarybuff id="18" amount="-1" /> <!-- sight --> <resistbuff toxic="3" asphyxiative="3" putrefying="3" /> <description text="It is thought, perhaps, that this mask will scare the disease away."/> </item> It's an artifact, but the artifact tag doesn't appear in the item tag. This is the case with some items. Artifacts WITH an artifact tag are krong-able. EDIT: After thoroughly searching through every itemDB.xml, I found out ONLY THE PLAGUE DOCTOR'S MASK has this problem (in the main game + expansions - can't say this about any mods).