It appears that Macrovision released IS12 SP2 for English and Japanese customers today. It should be noted ( as mentioned in the IS KB Article ) that a couple of the fixes resolve issues that were introduced in IS12 SP1. Personally I had not noticed these bugs since I'm in a 100% .NET environment these days ( Yippie, No COM ) and we don't do database changes in our installers.
A list of resolved issues can be found here. There is also a link to where to download on that page.