If you come across a Deployment Error like the one shown above during a deployment, follow the steps below for a possible solution.
1. Make a note of what Application and Environment the deployment was running against.
2. Login to the Automation Studio, open the relevant Application and navigate to the Environments tab within the Design tab.
3. Select the Environment that was used in the deployment, which should show a list of the server types used in the environment and the agents that are associated with them.
4. Check all server types for any agents that are listed more than once inside a server type as shown below
5. Once you find a duplicate agent, remove all copies of it from the server type and save.
6. Now go back in to add agents into the server type, add the agent back in once and save.
7. The deployment should now be able to run without the NonUniqueResultException error.