I've bug reported this and mentioned it in the bard boards several weeks ago. Had high hopes that a simple problem such as this might be fixed in 7.1 and figured I better put this here in the Lamannia board now that the next update is already being previewed.
Sustaining Song from the Virtuoso II PrE and Spellsong Vigor from the Spellsinger II PrE do not work on Warforged. In addition, they both seem to use the same programming as tavern drinks as indicated by the same audio being used for both (the 'ding' sound). If it's true that they use the same programming then warforged would simply need their tavern drink of the appropriate type applied when the song hits them instead of the fleshy version and all would be fixed.
Here's hoping that this fix can find its way into Update 8!