diff --git a/analyzers/src/SonarAnalyzer.CSharp/Rules/CastShouldNotBeDuplicated.cs b/analyzers/src/SonarAnalyzer.CSharp/Rules/CastShouldNotBeDuplicated.cs
index f34dc41a66e..8ab3e90dfd4 100644
--- a/analyzers/src/SonarAnalyzer.CSharp/Rules/CastShouldNotBeDuplicated.cs
+++ b/analyzers/src/SonarAnalyzer.CSharp/Rules/CastShouldNotBeDuplicated.cs
@@ -232,8 +232,8 @@ private static void ReportPatternAtCastLocation(SonarSyntaxNodeReportingContext
 
     private static bool IsEquivalentVariable(ExpressionSyntax expression, SyntaxNode typedVariable)
     {
-        var left = RemoveThisExpression(typedVariable).WithoutTrivia();
-        var right = RemoveThisExpression(expression).WithoutTrivia();
+        var left = CleanupExpression(typedVariable).WithoutTrivia();
+        var right = CleanupExpression(expression).WithoutTrivia();
 
         return left.IsEquivalentTo(right)
             || (StandaloneIdentifier(left) is { } leftIdentifier && leftIdentifier == StandaloneIdentifier(right));
@@ -245,8 +245,14 @@ static string StandaloneIdentifier(SyntaxNode node) =>
                 _ when node.IsKind(SyntaxKindEx.SingleVariableDesignation) => ((SingleVariableDesignationSyntaxWrapper)node).Identifier.ValueText,
                 _ => null
             };
+    }
 
-        static SyntaxNode RemoveThisExpression(SyntaxNode node) =>
-            node is MemberAccessExpressionSyntax { Expression: ThisExpressionSyntax } memberAccess ? memberAccess.Name : node;
+    private static SyntaxNode CleanupExpression(SyntaxNode node)
+    {
+        while (node is ParenthesizedExpressionSyntax parenthesized)
+        {
+            node = parenthesized.Expression;
+        }
+        return node is MemberAccessExpressionSyntax { Expression: ThisExpressionSyntax } memberAccess ? memberAccess.Name : node;
     }
 }
diff --git a/analyzers/tests/SonarAnalyzer.Test/TestCases/CastShouldNotBeDuplicated.cs b/analyzers/tests/SonarAnalyzer.Test/TestCases/CastShouldNotBeDuplicated.cs
index 6f75a08ff17..834e40bde0d 100644
--- a/analyzers/tests/SonarAnalyzer.Test/TestCases/CastShouldNotBeDuplicated.cs
+++ b/analyzers/tests/SonarAnalyzer.Test/TestCases/CastShouldNotBeDuplicated.cs
@@ -41,6 +41,22 @@ public void IgnoreMemberAccess(Fruit arg)
             _ = (Fruit)differentInstance.Property;
         }
 
+        // https://github.com/SonarSource/sonar-dotnet/issues/9491
+        if (arg.Property is Fruit)                  // Noncompliant
+        {
+            _ = ((Fruit)(arg.Property)).Property;   // Secondary
+        }
+
+        if (arg.Property is Fruit)                  // Noncompliant
+        {
+            _ = ((Fruit)((arg.Property))).Property; // Secondary
+        }
+
+        if (arg.Property is Fruit)                  // Noncompliant
+        {
+            _ = ((Fruit)arg.Property).Property;     // Secondary
+        }
+
         if (f.Property is Fruit)                    // Compliant, the cast is on a different instance
         {
             _ = (Fruit)differentInstance.Property;
@@ -128,6 +144,12 @@ public void TakeIdentifierIntoAccount(object x)
             var fruit = (Fruit)this.someField;
 //                      ^^^^^^^^^^^^^^^^^^^^^ Secondary
         }
+
+        if (someField is Fruit) // Noncompliant
+        {
+            var fruit = ((Fruit)(this.someField));
+//                       ^^^^^^^^^^^^^^^^^^^^^^^ Secondary
+        }
     }
 
     public void UnknownFoo(object x)