SCM - MS SQL Server Essentials Connection Error - No Permissions

I am using a domain account in SCM to monitor elements in the database. After I added Trusted_Connection=yes to the connection string it worked for all but 10 elements. I kept getting a permissions error for the objects. I changed all sorts of security settings for the account whose credentials I had assigned to the element. I then went into SQL Management Studio and configured logging for success and failed logins. I executed the test on the element and to my surprise the account being used was the polling engines machine account and not the domain user account. Emanon\poller-1$  instead of Emanon\user. Granting the machine account permissions to view the master and msdb. Now all the elements run just fine. Don't understand exactly why the different account is used from the Poller. I have to assume there is a service running as the local machine that isn't using the connection string to connect.