2000 V70XC Cat Converter P0422

[MilehighV70XC]

You mentioned a slight oil leak from the turbo and the code came on after a long trip. The oil leak could be your problem. Do you see any oil residue on the cat?
My car kept getting the same code. I had a oil leak from where the turbo oil return line goes into the block. On long trips in the mountains, where I was boosting the turbo often, the oil would blow back onto the cat converter. The high temperature of the cat would then bake the oil, causing the cat to run hotter. I fixed the oil leak and the code never came back. The cat converter works perfect still.