Some fraud incidents are too severe for credit unions to bounce back from.
Seventeen failures and one voluntary liquidation recorded last year, agency said.
Small credit union also had its former NCUA examiner on its board, according to Inspector General's report.
New report cites CEO's aggressiveness and risk-taking, compliant board, lax oversight in California credit union failure.
After 15 months in conservatorship, the NCUA liquidated the $259 million Chetco FCU of Harbor, Ore., effective Dec. 31.