DependencyWalker.DiscoverDependencies fails with System.ArgumentException: Item has already been added.

We hit this when we had a few old stored procedures referring to the same dropped table with different casing for database name. I see commented out code at https://github.com/microsoft/sqlmanagementobjects/blob/main/src/Microsoft/SqlServer/Management/Smo/DependencyTree.cs#L198 that might have fixed this issue, not sure why it's been commented out though.

Microsoft.SqlServer.Management.Smo.FailedOperationException: Discover dependencies failed. 
 ---> System.ArgumentException: Item has already been added. Key in dictionary: 'Server[@Name='SERVER']/Database[@Name='database']/UnresolvedEntity[@Name='nonexisting_table' and @Schema='dbo']'  Key being added: 'Server[@Name='SERVER']/Database[@Name='DATABASE']/UnresolvedEntity[@Name='nonexisting_table' and @Schema='dbo']'
   at Microsoft.SqlServer.Management.Smo.DependencyTree..ctor(Urn[] urns, DependencyChainCollection dependencies, Boolean fParents, Server server)
   at Microsoft.SqlServer.Management.Smo.DependencyWalker.DiscoverDependencies(Urn[] urns, Boolean parents)

Comienza en src/Microsoft/SqlServer/Management/Smo/DependencyTree.cs alrededor de la línea 198 y sigue DependencyWalker.DiscoverDependencies para determinar cómo se usan como claves las entidades no resueltas. Reproduce el fallo con referencias que solo difieran en las mayúsculas y minúsculas del nombre de la base de datos y, después, evalúa la lógica comentada. Se considera terminado cuando el descubrimiento de dependencias ya no lanza una excepción si referencias no resueltas equivalentes usan mayúsculas y minúsculas diferentes.