I redeemed for Target more than a week ago, and yesterday it showed as failed in my account. That's when I noticed it's not on the reward page anymore. Anybody's guess if it'll come back or not.

Edited to add: Just got an email telling me the cards are out of stock:
"Target eGift Cards are still unavailable at this time but we are working hard to bring them back and expect them to be available within the next 3 weeks."