When Palmer Luckey’s Erebor Bank launched earlier this year, it made an attractive pitch to lure new crypto customers: It would convert their stablecoins to cash for free.

But Erebor wound up pulling the offer after several months, after sophisticated crypto trading firms sniffed out a way to make an easy profit out of the offer—at a cost to Erebor. The episode demonstrates that the young bank is still figuring out how to manage the risks of serving the cryptocurrency industry, a world of fast-moving financial flows, colorful characters and unusual business models.