Strange Ego/Curse combination

[Monkey Face]

I found an early game shield with unidentified properties. When I attacked a blue jelly I learned that it was a Resist Cold shield with the Chilled to the Bone curse which makes me vulnerable to cold attacks but resistant to fire. Do the cold resistance and the curse cancel each other out making this essentially a shield of resist fire until I remove the curse?

[wobbly]

To a degree:

curse only = cold vulnerability
curse + resist cold = no cold resist, no vulnerability
curse + resist cold + resist cold (other equipment source) = still no cold resist
curse + resist cold + temp resist cold (potion) = cold resist
curse + cold immunity = cold resist, no immunity