Just like the article says, we can blame the states.  Not only are the states submitting incomplete or inaccurate information, they are submitting more background check requests than are necessary.

If I buy a pistol in Hawaii every month, and renew my long gun permit annually, that's 13 NICS requests on me.  If I already have 6 pistols and who knows how many AR-15s, what is the purpose for more and more NICS requests?  Nothing will have changed month to month, and if my mental state DOES change, I can do plenty of damage with the guns I already have.  Short of being hospitalized or arrested, the chances I'll be caught in a records check is zero!

Trying to make the process overly cautious (or overly difficult) will only further overwhelm a system that can't keep up with demand.  States like Hawaii which think they are making the public safer by requiring a check with each and every handgun purchased are effectively doing the opposite.