AgilePoint NX server auto appends the domain name to the username while assigning the task to them in case username is specified in the participant property and it does not contain domain name. This is for the convenience of process designer so that he does not explicitly add the domain name to username which is dynamically resolved at runtime.
This is a convenience but can also lead to undesirable result if you actually intended for username to be without domain name, For e.g. if you are using usernames from Windows Azure AD, Salesforce which are in User Principle Name (email) format, you wish to keep them without domain name but if you might see a username for e.g. xyz\nishant.shrivastava©xyz.com
There is a easy way to turn this default behavior off.
Open netflow.cfg from C:\Program Files\AgilePoint\AgilePointServerInstance or whatever is your install location.
Update the node <domain> to add following attribute: checkbackslash=”false”
Restart AgilePoint Server from services.msc.
Once you do that, you will see dynamically resolved username in desired format i.e. nishant.shrivastava©xyz.com