Are you sure that there are no rollbacks on initial BEGIN DIALOG CONVERSATION or SEND ON CONVERSATION? If the client, or whoever initializes the conversation, issues a rollback then this counter is incremented.

the following example will increase the counter by one, and if you add a SEND statement in the transaction, it will be incremented by two.

begin tran

declare @handle uniqueidentifier

begin dialog conversation @handle

from service [sender_service]

to service 'receiver_service'

on contract [contract]

rollback

You need to find out if the client (initiator) is doing any rollbacks.