Credit check failure hold released automatically by credit check processor though credit limit is 0

Hi all,

Credit check failure hold was applied on an order and automatically released by the credit check processor with the release comment 'Credit Check EngineCredit Check Processor activity has done credit checking using Ordering level credit check rule.' even though the credit limit for the customer is zero. What might be the validation done by the program to release the hold automatically? Kindly help on this