I was playing a best of 3 standard ranked after I had previously played a best of three standard ranked with the same deck when I noticed a weird thing going on with my deck when sideboarding. Once we got to sideboarding after the first game my deck was pre-sideboarded to how I had sideboarded in the last game of the previous best of three. None of the pre-sideboard cards were actually in my deck for the first game, but it was really annoying to figure how to desideboard my deck and then resideboard for the new match. I have never seen anything like this before today.