Can the sound man please turn up Stevie's mic ?!?!?! 
It appears that the Mac were having some major sound problems at the US Festival on this given evening. Lindsey's mic cuts out on the chords of the set opener "Second Hand News", then Chris' mic begins to blare at the end of that tune. Now Stevie's mic is fading out. Perhaps this is why their US Festival appearance hasn't seen an official release.