diff --git a/specification/timeseriesinsights/resource-manager/Microsoft.TimeSeriesInsights/stable/2020-05-15/timeseriesinsights.json b/specification/timeseriesinsights/resource-manager/Microsoft.TimeSeriesInsights/stable/2020-05-15/timeseriesinsights.json
index 190ce3b7cb64..4bd8ce2a695c 100644
--- a/specification/timeseriesinsights/resource-manager/Microsoft.TimeSeriesInsights/stable/2020-05-15/timeseriesinsights.json
+++ b/specification/timeseriesinsights/resource-manager/Microsoft.TimeSeriesInsights/stable/2020-05-15/timeseriesinsights.json
@@ -1406,7 +1406,21 @@
     },
     "EnvironmentUpdateParameters": {
       "type": "object",
+      "discriminator": "kind",
       "properties": {
+        "kind": {
+          "type": "string",
+          "readOnly": true,
+          "description": "The kind of the environment.",
+          "enum": [
+            "Gen1",
+            "Gen2"
+          ],
+          "x-ms-enum": {
+            "name": "EnvironmentKind",
+            "modelAsString": true
+          }
+        },
         "tags": {
           "type": "object",
           "additionalProperties": {
@@ -1419,6 +1433,7 @@
     },
     "Gen1EnvironmentUpdateParameters": {
       "type": "object",
+      "x-ms-discriminator-value": "Gen1",
       "properties": {
         "sku": {
           "$ref": "#/definitions/Sku",
@@ -1439,6 +1454,7 @@
     },
     "Gen2EnvironmentUpdateParameters": {
       "type": "object",
+      "x-ms-discriminator-value": "Gen2",
       "properties": {
         "properties": {
           "x-ms-client-flatten": true,
@@ -1618,9 +1634,6 @@
         },
         {
           "$ref": "#/definitions/EnvironmentResourceProperties"
-        },
-        {
-          "$ref": "#/definitions/ResourceProperties"
         }
       ],
       "required": [
@@ -1654,9 +1667,6 @@
       "allOf": [
         {
           "$ref": "#/definitions/EnvironmentResourceProperties"
-        },
-        {
-          "$ref": "#/definitions/ResourceProperties"
         }
       ],
       "description": "Properties of the Gen2 environment."
@@ -1900,8 +1910,22 @@
       "description": "Parameters supplied to the Create or Update Event Source operation for an IoTHub event source."
     },
     "EventSourceUpdateParameters": {
+      "discriminator": "kind",
       "type": "object",
       "properties": {
+        "kind": {
+          "type": "string",
+          "readOnly": true,
+          "description": "The kind of the event source.",
+          "enum": [
+            "Microsoft.EventHub",
+            "Microsoft.IoTHub"
+          ],
+          "x-ms-enum": {
+            "name": "EventSourceKind",
+            "modelAsString": true
+          }
+        },
         "tags": {
           "type": "object",
           "additionalProperties": {
diff --git a/specification/timeseriesinsights/resource-manager/readme.md b/specification/timeseriesinsights/resource-manager/readme.md
index 6e5d24befcad..ab4686fed747 100644
--- a/specification/timeseriesinsights/resource-manager/readme.md
+++ b/specification/timeseriesinsights/resource-manager/readme.md
@@ -68,6 +68,15 @@ input-file:
 
 ``` yaml
 directive:
+  - suppress: READONLY_PROPERTY_NOT_ALLOWED_IN_REQUEST
+    where: 
+      - $.definitions.EnvironmentUpdateParameters.properties.kind
+      - $.definitions.EventSourceUpdateParameters.properties.kind
+    from: timeseriesinsights.json
+    reason: This property is the discriminator for polymorph, but it can not be in request body.
+  - suppress: OAV131 # DISCRIMINATOR_NOT_REQUIRED
+    from: timeseriesinsights.json
+    reason: kind is a non-settable property from the client in patch method.
   - suppress: R3025  # Tracked resource 'XXX' must have a get operation
     where:
       - $.definitions.StandardEnvironmentResource