Not sure about Hawaiian specifically, but in general e-rewards seems to be having problems with some redemptions. In my case it's been for a couple of different gift cards this month. Some of my redemptions have gone as normal, and the e-card is received no later than 24 hours after confirmation. Others seem to require a polite inquiry to e-rewards several days after redemption. I can't prove it, but it seems that an inquiry prompts them to expedite, or at least initiate, manually re-processing the reward. They say that they are aware of the problem, and ask for patience as it may take 7-10 days to manually process.