Savvy credit-card users have forced J.P. Morgan Chase to pony up more in rewards payments than the bank originally projected.

Buried in an otherwise positive second-quarter earnings report Friday, in which the bank announced a record $8.32 billion profit, was the admission that credit-card customers were redeeming points faster than anticipated, resulting in a $330 million charge.

“This is maybe larger than we have seen over the course of the last several years,” said Marianne Lake, the chief financial officer, during a conference call with reporters. “We do pretty regularly review our rewards liability in light of evolving consumer behavior.”

Credit-card issuers scrambling to sign coveted high-spenders have sparked a rewards war in recent years. J.P. Morgan ratcheted up the competition in 2016 with its Sapphire Reserve card, which came with lavish perks including a 100,000-point signing bonus and triple rewards for travel and dining. The initial run of that card sapped quarterly profit by as much as $300 million, the bank said in December 2016.

