Mendelson and Koritala were both optimistic that the federal marketplace could make software adjustments to reduce the number of deficient applications being transmitted to insurers, and reduce the time and effort expended getting back to applicants.  But, Mendelson warned, "I'm going to say they have one month to get their act together on the IT" to reduce the lag in verifying and finalizing applications. If that doesn't happen, the government could "potentially increase the length of the enrollment period."  People have until Dec. 15 to enroll and pay for a plan to be effective Jan. 1. The enrollment deadline for 2014 is March 31.  Mendelson's one-month time frame reflects a wave of enrollment expected in late November as people try to beat the cutoff.  "If we continue to see these issues through the next three or four weeks there's a lot of concern about how many people will have effective coverage by Jan. 1," said Dan Schuyler, director of the consultancy Leavitt Partners.  Though he had not heard about the specific problem of insurers' getting large numbers of applications with missing or questionable data, he said that right up until Tuesday's launch of the exchanges, he heard about difficulties with test transmissions to insurers.  (Read more: The selling of Obamacare)  Specifically, Schuyler said, insurers selling plans on the exchange were not receiving data about all individuals supposedly enrolling in those plans during the tests being conducted.  In its press release Friday, HHS said, "Experts are working around the clock to make the site better able to meet the volume created by consumers' overwhelming interest in their new health coverage options."  "There have been sustained improvements to the consumer experience and that trend is expected to continue."  Experts said that if the lag in processing enrollments continues on a large scale, insurers expect the federal government to tell them that they must provide benefits to people even as applications are still being processed.  "In talking to some of the insurers, they pretty much assume that even if there are issues, the feds will say, 'You know what, it's your problem, they've signed up,' " said Koritala.  —By CNBC's Dan Mangan. Follow him on Twitter @_DanMangan.
As few as 1 in 100 applications on the federal government's exchange contains enough information to enroll the applicant in a plan.