The most common reason why a member might have a hold group that's different from what would normally be associated with their Tiered Service Level is because of delinquency.  During daily delinquency monitoring the system sets the Electronic Deposit Hold Group to a certain code when members go delinquent, according to your credit union's settings in both the Member in Good Standing feature as well as your Delinquency Aging Levels configuration.  If the system considers a loan to be delinquent at the time daily monitoring is done, the hold group is adjusted, even if Tiered Services had set it to something else previously.