Actually I went and tested again just to confirm and something strange happened. The first attack after the good buffs did the damage I'd expect, but then the second was back down to Outrage levels of damage. It's a difference of ~8000 so it's not just variance, not sure what happened there.
Well, as the first post says:
Originally Posted by sanahtlig
-- Intriguingly, it appeared to increase normal attack damage in the SAME ROUND it was applied, but this bonus did not carry over to subsequent rounds, suggesting a strange system glitch rather than a design oversight.--
Bleh, that's what I get for not reading I guess. The second attack was fatal so I couldn't test any further, I'll try again later but it's looking like it's unfixed