Suppose to set custom attributes like this

{"id":"urn:ietf:params:scim:schemas:extension:enterprise:2.0:User","name":"User","description":"Enterprise User","schema":"urn:ietf:params:scim:schemas:extension:enterprise:2.0:User","endpoint":"/Users","attributes":[{"name":"forcePasswordResetAtLogin","type":"String","multiValued":true,"description":"","schema":"urn:ietf:params:scim:schemas:extension:enterprise:2.0:User","readOnly":false,"required":false,"caseExact":false},{"name":"tapRoles","type":"String","multiValued":true,"description":"","schema":"urn:ietf:params:scim:schemas:extension:enterprise:2.0:User","readOnly":false,"required":false,"caseExact":false}]}

where tapRoles is multivalue and is serialized, before sending the payload to the SCIM api, after the forcePasswordResetAtLogin.

tapRoles is serialized as single valued object like this "tapRoles":"test1" instead of "tapRoles":["test1"]