Excellent screed/rant by Dave Mandl over on Rumpus.net. Neatly explains the sore point of incorrect dating on music streaming and download sites.
Interestingly, one of the commenters says that the reason why the labels feed this incorrect information to the streaming databases is so that they get the (tiny) payment registered to the more recent release. Presumably this make accounting easier for the labels. From a cursory look around a few other services, it appears that those using the All Music API do get the dates correct.