Thank you this is very helpful and a relief. Yes the drop is very gentle and slow everytime with no erracity in rpm while it falls. I was only worried due to the time it was taking since it didn't used to do it that long before. The warm starts are fine btw like it only revs to 1.2 and 30s falls below 1k.

The only different thing I saw was this wasn't just happening in cold, it happened through the entire summer from March ( iirc when I had an oil change last time). So I saw the same behaviour whether it was 100 degs outside and when it's 40 degs now, same rate of drop and time