How is AH Hold getting assigned to Customer Master?

We are getting a number of Customer records on a daily basis where AH is being assigned to the Hold Orders Code (alias HOLD) on Billing Page 2.  We don't have anything set up to my knowledge to use the AH process.  The versions of sales order entry do not have the AH code setup in the Hold Codes tab of processing options.  I'm thinking there must be some other process that is assigning the AH directly to the customer record.  Does anyone know where the assignment of the AH hold could be coming from?    We are on applications version