I'm in the middle of changing out my DP and was having a really hard time removing the front O2 sensor from the OEM DP. By the time I finally got it off, it looked like this, like the threads melted together.
Mine did the same thing. Was crazy to get it off and the threads stripped. I straightened then the best I could, but seeing the DP is staying on the car even when I sell it I wasn't too worried and put it on the new DP.