Originally Posted by Blizzard
We recently fixed a much publicized rogue bug where the Glyph of Backstab interacted with Dirty Deeds to cause too much damage to stunned targets (basically attacks other than Backstab were benefiting). We were concerned that with this bug fixed, Subtlety rogues would suffer a dps loss. Therefore we changed Sinister Calling to increase the damage bonus to Backstab and Hemorrhage from 5% up to 10% with max ranks.
This change is coming in patch 3.1, we have not hotfixed anything at this time.