Trying to add a SCIM schema override file always results in an error

Question

Hello, 
 I am tasked with integrating user provisioning for an Appian applications platform in OIM 9.2. The responsible Appian dev team has installed an Appian community built SCIM module so I have a target SCIM Service provider that I can integrate with a SCIM connector. Setup and initial config of this SCIM connector in the synchronization editor has gone well but now I need to add an extension on the default SCIM core User schema. The Appian SCIM module however does not implement the Schemas and ResourceTypes endpoints. No worries I thought because the SCIM connector connection editor allows me to add Schema override files for exactly this scenario. 
 But when I add the override file with my extension schema definition and use the Check button an error pops up saying 'An item with the same key has already been added'. My extension schema is small and only contains three unique attributes. In the connection editor I had to clear the fields for the Schemas & ResourceTypes endpoints so that the SCIM connector would use the default SCIM schema it knows internally. I cannot understand why this error pops up when I am most certainly using unique attribute names and unique schema namespace. 
 I've checked with Copilot and Scim.dev to make sure my schema override file is correct and wouldn't cause any such conflict. And then there is another strange thing. If I remove all but one attribute in my schema override file the error does not occur but I do get a message stating 'Following identified schema types are not SCIM 2.0 compliant: ssin ()' even though I've verified my schema file to be compliant with SCIM2.0. 
 I must say it's getting quite confusing. The connection editor has the following description on the schema override files "Additional schema data can be provided here using schema override files." but the documentation on this subject says 'Contains the complete schema definition of the cloud application.' So I've also tried to use the default SCIM schema downloadable from scim.dev but this results in the same error. Even creating a new SCIM connector and immediately adding the override files results in the same error. 
 Is this possibly a bug in the connection editor? 
 Here is my extension schema: 
 { "id": "urn:ietf:params:scim:schemas:extension:redacted:1.0:User", "name": "redacted", "description": "Custom extension schema for redacted attributes extending the User object", "attributes": [ { "name": "ssin", "type": "string", "multiValued": false, "required": true, "mutability": "readWrite", "returned": "always", "uniqueness": "server" }, { "name": "departmentNumber", "type": "string", "multiValued": false, "required": true, "mutability": "readWrite", "returned": "default" }, { "name": "departmentName", "type": "string", "multiValued": false, "required": true, "mutability": "readWrite", "returned": "default" } ] }

tlindner · Answer

This is exactly what the Administration Guide for SCIM connector says ( https://docs.oneidentity.com/bundle/one-identity-manager_connecting-to-cloud-applications_9.3/page/sources/cloudts/ucisyncconfigexpert.htm ):

On the Schema definition page, enter the path for the override files. Both files must exist.

Schema override file : Contains the complete schema definition of the cloud application.

Resource configuration override file : Contains the full resource definition of the cloud application.

NOTE: If override file are given in the synchronization configuration files they replace a schema definition on the server.