Soul core of Tacati decreased my cold/fire/light res

I socketed a 3rd Soul Core of Tacati onto my bloodmage, into my Focus which had no other runes/socketables in it and it knocked down my cold res to -1 from about 60ish and my fire res from like 111 to 61 and my lightening res was like 146ish and is now 80.

im not sure if this is a bug or if i am missing something, but it doesnt make sense to me, the only thing that changed on the build was adding a 3rd Soul Core of Tacati.