FAQ: FinancialForce PSA: Duplicate Value on Record
If multiple projects are on the same report within Expensify, we export each of those projects to their own Expense Report in FinancialForce.
When exporting from Expensify, if at least one project fails to export, the remaining projects will also fail. When attempting to export again, this error will appear to indicate that one or more of the projects were successfully exported, creating a possible duplicate.
To clear the error, you'll need to delete any expense reports found under the Expensify report ID in Financial Force.
Then sync the connection within Expensify by going to Settings > Policies > Groups >[Policy Name] > Connections > Sync Now, and then attempt to export again.