Because of the huge amount of bounty fraud that was not identified by the bounty mangers processes. For example bounty hunters identiifed the plagerism checks and made deliberate type to get around that, wrote articles that got approved that had no relevance to the project that got approved

Basically it appears that a huge amount of bounty was scam or fraud so has required a full re audit as reliance could not be placed on the managers validations as hunters had found ways around his controls in place