Data point that the counting of two rooms a night may have been sorted. I rolled over 8 nights. I've already had a 3 night stay with 2 rooms. On Tuesday (when 2020 begun) I was showing as 14 nights progress to renewing Diamond. Today it shows (correctly is 2 rooms don't count as 2 nights) 11 nights.

At the same time my points balance went down by 1000. On checking it was the my way bonus for the 2nd room, so I suppose this is correct too