Government officials and insurers were scrambling to iron out the pricing quirks quickly, according to the people, to avoid alienating the initial wave of consumers.
A failure by consumers to sign up online in the hotly anticipated early days of the "exchanges" is worrisome to insurers, which are counting on enrollees for growth, and to the Obama administration, which made the exchanges a centerpiece of its sweeping health-care legislation.
If not resolved by the Oct. 1 launch date, the problems could affect consumers in 36 states where the federal government is running all or part of the exchanges. About 32 million uninsured people live in those states, but only a fraction of them are expected to sign up in the next year.
The remaining 14 states are running separate marketplaces with their own software. One of those states, Oregon, has already announced that it would delay some features to fix software bugs, though consumers will be able to enroll offline.