Well according to the Brady Campaign that's the case.

California criminal database: Computerized log poorly maintained - latimes.com

The criminal records system California relies on to stop... violent felons from buying guns is so poorly maintained that it routinely fails to alert officials to a subject's full criminal history.
"There are obviously serious public safety implications if that database is incomplete," said Dennis Henigan, president of the Brady Center to Prevent Gun Violence, a national gun-control group. "Every record missing from the system could be someone who is too dangerous to buy a gun."