Doktor Avalanche
See eZine.
I think it's just short. Getting smaller each month 
As there are fewer bugs to fix, perchance..
Not being a coder, this is mere speculation, but is it possible that some bugs are quicker to fix than others?
The ones that are quicker to fix are being fixed quickly, the longer term ones are taking longer?
As the quick ones are fixed quickly, more of them can be fixed in a short time? As the list diminishes, there will be fewer fixes that take longer to deal with?
I have no idea, I guess only Cakwalk know, so all else is speculation. They seem to be doing a great job. I will leave it up to their discretion, as they are the only ones in possession of all the facts.