Yeah, no policy memo this year! Many MPP programs never had policy memo as a part of their application. Also, in previous years they had "leadership essay" which is now all incorporated in this "SOP" wonna be....
In my opinion, the rise in the number of applications that HKS saw in last years could be one of the reasons. So now thay have easier job of reading only one essay, instead of 3. Also, they moved the application deadline to early December, while in last years it was early January. But still, the answers will be given at the same time. So I am guessing they want to make it easier for their adcoms.
Where are you planning to apply? MPP, MPA/ID ? Some other schools besides HKS ?