This may happen in the following scenarios:
1. Agreement additions were deleted in Connectwise and/OR
2. site\_agreement mappings were deleted in the integration.
Both instances create an agreement addition.
When a new site\_agreement mapping is created in the integration, it does not have an addition ID mapping. When the first sync is run, if a site\_agreement does not have an addition ID mapping, a new addition will be created.
If the site\_agreement mapping is deleted and recreated, it will not have an addition ID mapping and a new addition will be created.
If a site\_agreement has an addition ID mapping, but the addition in ConnectWise has been deleted, then the integration will create a new addition and update the site\_agreement addition ID mapping.
The integration can not map to existing agreement additions. It is meant to create the addition and hold the mapping to it.