Hi,
Documents may be delivered more than once if you do not have a duplicate checking mechanism in place.
Please Check
In My webMethods: Messaging > Broker Servers > Clients
On the Client Details page, click the Configuration tab to view configuration information about the client. please check the field
Pulish Sequence Number- which is Specifies the last sequence number for published documents received by this client. A publishing client program assigns sequence numbers to documents to allow Broker to recognize
and discard duplicate documents from the same publisher. A sequence number of 0 typically indicates that the publishing client does not use publish sequence numbers
#Integration-Server-and-ESB#webMethods