I wanted to take a moment to discuss with each of you a change that was made to all spell casting speed modifying spells and abilities, including the Warlock spell "Curse of Tongues", the Rogue's "Mind-Numbing Poison" as well as several creature spells, which unfortunately wasn't listed in the patch notes. Such spells and abilities will no longer have an affect on spells that had a casting time before talents that are made instant after talents. This list includes Arcane Explosion and Corruption.
I apologize that we didn't provide notification of such change before the release of the patch, and moving forward we will continue in our efforts of insuring all details, no matter how minor, are included in the patch notes.
Online Community Representative