diff --git a/OpenAPI/TS28104_MdaNrm.yaml b/OpenAPI/TS28104_MdaNrm.yaml
index 89aa349ac731d526530fc859204a12617ef07f28..ffe182c4f902a383e39bd864f4a065d41e335b9b 100644
--- a/OpenAPI/TS28104_MdaNrm.yaml
+++ b/OpenAPI/TS28104_MdaNrm.yaml
@@ -17,12 +17,14 @@ components:
 
     MDATypes:
       type: array
+      uniqueItems: true
       items:
         type: string
         readOnly: true
 
     MDAOutputs:
       type: array
+      uniqueItems: true
       items:
         $ref: '#/components/schemas/MDAOutputPerMDAType'
 
@@ -45,6 +47,7 @@ components:
           type: string
         mDAOutputIEFilters:
           type: array
+          uniqueItems: true
           items:
             $ref: '#/components/schemas/MDAOutputIEFilter'
 
@@ -78,6 +81,7 @@ components:
           properties:
             timeDurations:
               type: array
+              uniqueItems: true
               items:
                 $ref: 'TS28623_ComDefs.yaml#/components/schemas/TimeWindow'
         - type: object
diff --git a/OpenAPI/TS28104_MdaReport.yaml b/OpenAPI/TS28104_MdaReport.yaml
index 8462541694b5d80c8e8aa4577648195b7706a4b3..4b76b47a4359d7c146290e1c8c2e9557be921bf9 100644
--- a/OpenAPI/TS28104_MdaReport.yaml
+++ b/OpenAPI/TS28104_MdaReport.yaml
@@ -23,6 +23,7 @@ components:
           readOnly: true
         mDAOutputList:
           type: array
+          uniqueItems: true
           items:
             $ref: '#/components/schemas/MDAOutputEntry'
         analyticsWindow: