Hey,
I also misunderstood the function of the lamps. Assuming the event currency was actually the polishing clothes that can no longer be obtained after event ends. But I thought the lamps would still work during the reward redemption period, only that they can no longer be upgraded into wishing lamps. The jackpots for example always lasted through the reward redemption period, I have a years old juggernaught jackpot on one char, still working. xD Of course I can read item tooltips but I also think NC should have announced more clearly that the lamps will stop working immediately after patch day. I had about ten lamps left at the end and even could've opened/transmuted them, but started to slack because of this 5h cooldown. I mean, who wants to set an alarm clock in the middle of the night when they have to work the next day?