diff --git a/Tests/Integration/ClientIntegrationTests.swift b/Tests/Integration/ClientIntegrationTests.swift
index 3dc64cc7..768822d8 100644
--- a/Tests/Integration/ClientIntegrationTests.swift
+++ b/Tests/Integration/ClientIntegrationTests.swift
@@ -745,4 +745,37 @@ final class ClientIntegrationTests: XCTestCase {
         try await c1.deactivate()
         try await c2.deactivate()
     }
+
+    func test_duplicated_local_changes_not_sent_to_server() async throws {
+        try await withTwoClientsAndDocuments(self.description, detachDocuments: false) { c1, d1, c2, d2 in
+            try await d1.update { root, _ in
+                root.t = JSONTree(initialRoot:
+                    JSONTreeElementNode(type: "doc",
+                                        children: [
+                                            JSONTreeElementNode(type: "p", children: [JSONTreeTextNode(value: "12")]),
+                                            JSONTreeElementNode(type: "p", children: [JSONTreeTextNode(value: "34")])
+                                        ])
+                )
+            }
+
+            try await c1.sync()
+            try await c1.sync()
+            try await c1.sync()
+            try await c1.detach(d1)
+
+            try await Task.sleep(nanoseconds: 3_000_000_000)
+
+            try await c2.sync()
+
+            let d1XML = await(d1.getRoot().t as? JSONTree)?.toXML()
+            let d2XML = await(d2.getRoot().t as? JSONTree)?.toXML()
+            XCTAssertEqual(d1XML, /* html */ "<doc><p>12</p><p>34</p></doc>")
+            XCTAssertEqual(d2XML, /* html */ "<doc><p>12</p><p>34</p></doc>")
+
+            try await c2.detach(d2)
+
+            try await c1.deactivate()
+            try await c2.deactivate()
+        }
+    }
 }
diff --git a/Tests/Integration/IntegrationHelper.swift b/Tests/Integration/IntegrationHelper.swift
index d87fdd01..6d74a069 100644
--- a/Tests/Integration/IntegrationHelper.swift
+++ b/Tests/Integration/IntegrationHelper.swift
@@ -17,7 +17,7 @@
 import XCTest
 @testable import Yorkie
 
-func withTwoClientsAndDocuments(_ title: String, _ callback: (Client, Document, Client, Document) async throws -> Void) async throws {
+func withTwoClientsAndDocuments(_ title: String, detachDocuments: Bool = true, _ callback: (Client, Document, Client, Document) async throws -> Void) async throws {
     let rpcAddress = "http://localhost:8080"
 
     let docKey = "\(Date().description)-\(title)".toDocKey
@@ -36,11 +36,13 @@ func withTwoClientsAndDocuments(_ title: String, _ callback: (Client, Document,
 
     try await callback(c1, d1, c2, d2)
 
-    try await c1.detach(d1)
-    try await c2.detach(d2)
+    if detachDocuments {
+        try await c1.detach(d1)
+        try await c2.detach(d2)
 
-    try await c1.deactivate()
-    try await c2.deactivate()
+        try await c1.deactivate()
+        try await c2.deactivate()
+    }
 }
 
 protocol OperationInfoForDebug {}