Atari/Obsidian have released a hotfix.  Unlike other hotfixes, I don't think you need this one if you are already patched up to 1.21, as my version number remained at 1.21.1549 after the hotfix.  I think that the hotfix simply downloads some voice files for the Mask of Betrayer official campaign that were inadvertently deleted by Storm of Zehir.  Still, if you have time, you may want to get it to be sure.  It was a fairly large download, so allow some time.