diff --git a/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng1701DuplicatePluginTest.java b/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng1701DuplicatePluginTest.java
index f5431e275..81cce8eea 100644
--- a/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng1701DuplicatePluginTest.java
+++ b/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng1701DuplicatePluginTest.java
@@ -55,17 +55,12 @@ public void testit() throws Exception {
             // expected with Maven 4+
         }
 
-        String logLevel;
-        if (matchesVersionRange("(,4.0.0-alpha-1)")) {
-            logLevel = "WARNING";
-        } else {
-            logLevel = "ERROR";
-        }
-
         List<String> lines = verifier.loadLines(verifier.getLogFileName(), "UTF-8");
         boolean foundMessage = false;
         for (String line : lines) {
-            if (line.startsWith("[" + logLevel + "]")
+            // Maven < 3.10.0 and rc releases use [WARNING]; Maven 3.10.0+ (VALIDATION_LEVEL_MAVEN_3_1
+            // strict, post-rc-1) and Maven 4+ use [ERROR]. Accept either level.
+            if ((line.startsWith("[WARNING]") || line.startsWith("[ERROR]"))
                     && line.indexOf(
                                     "duplicate declaration of plugin org.apache.maven.its.plugins:maven-it-plugin-expression")
                             > 0) {
diff --git a/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng3719PomExecutionOrderingTest.java b/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng3719PomExecutionOrderingTest.java
index 775bc360e..295bc9ec0 100644
--- a/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng3719PomExecutionOrderingTest.java
+++ b/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng3719PomExecutionOrderingTest.java
@@ -36,7 +36,9 @@
 public class MavenITmng3719PomExecutionOrderingTest extends AbstractMavenIntegrationTestCase {
 
     public MavenITmng3719PomExecutionOrderingTest() {
-        super("[2.0.11,2.1.0-M1),[2.1.0-M2,4.0.0-alpha-1)");
+        // Maven 3.10.0+ treats duplicate plugin declarations as errors (VALIDATION_LEVEL_MAVEN_3_1 strict)
+        // so the test fixture was updated to use a single merged plugin declaration instead.
+        super("[2.0.11,2.1.0-M1),[2.1.0-M2,)");
     }
 
     /**
diff --git a/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng4005UniqueDependencyKeyTest.java b/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng4005UniqueDependencyKeyTest.java
index ebff7e8f8..4f224eb00 100644
--- a/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng4005UniqueDependencyKeyTest.java
+++ b/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng4005UniqueDependencyKeyTest.java
@@ -90,17 +90,13 @@ private void test(String project) throws Exception {
             // expected with Maven 4+
         }
 
-        String logLevel;
-        if (matchesVersionRange("(,4.0.0-alpha-1)")) {
-            logLevel = "WARNING";
-        } else {
-            logLevel = "ERROR";
-        }
-
         List<String> lines = verifier.loadLines(verifier.getLogFileName(), "UTF-8");
         boolean foundMessage = false;
         for (String line : lines) {
-            if (line.startsWith("[" + logLevel + "]") && line.indexOf("must be unique: junit:junit:jar") > 0) {
+            // Maven < 3.10.0 and rc releases use [WARNING]; Maven 3.10.0+ (VALIDATION_LEVEL_MAVEN_3_1
+            // strict, post-rc-1) and Maven 4+ use [ERROR]. Accept either level.
+            if ((line.startsWith("[WARNING]") || line.startsWith("[ERROR]"))
+                    && line.indexOf("must be unique: junit:junit:jar") > 0) {
                 foundMessage = true;
             }
         }
diff --git a/core-it-suite/src/test/resources/mng-3719/pom.xml b/core-it-suite/src/test/resources/mng-3719/pom.xml
index ddd2c7334..b01b85103 100644
--- a/core-it-suite/src/test/resources/mng-3719/pom.xml
+++ b/core-it-suite/src/test/resources/mng-3719/pom.xml
@@ -34,6 +34,10 @@ under the License.
 
   <build>
     <plugins>
+      <!-- Merged into a single plugin declaration to avoid duplicate plugin errors.
+           The original test had two separate declarations of maven-it-plugin-log-file which were
+           merged by Maven < 3.10.0. Maven 3.10.0+ treats duplicate plugin declarations as errors
+           (VALIDATION_LEVEL_MAVEN_3_1 strict mode), so the executions are combined here. -->
       <plugin>
         <groupId>org.apache.maven.its.plugins</groupId>
         <artifactId>maven-it-plugin-log-file</artifactId>
@@ -49,41 +53,34 @@ under the License.
               <logFile>target/step-1.properties</logFile>
             </configuration>
           </execution>
-        </executions>
-      </plugin>
-      <plugin>
-        <groupId>org.apache.maven.its.plugins</groupId>
-        <artifactId>maven-it-plugin-expression</artifactId>
-        <version>2.1-SNAPSHOT</version>
-        <executions>
           <execution>
-            <id>step 2</id>
+            <id>step 3</id>
             <goals>
-              <goal>eval</goal>
+              <goal>reset</goal>
             </goals>
             <phase>validate</phase>
             <configuration>
-              <outputFile>target/step-2.properties</outputFile>
-              <expressions>
-                <expression>project/properties</expression>
-              </expressions>
+              <logFile>target/step-3.properties</logFile>
             </configuration>
           </execution>
         </executions>
       </plugin>
       <plugin>
         <groupId>org.apache.maven.its.plugins</groupId>
-        <artifactId>maven-it-plugin-log-file</artifactId>
+        <artifactId>maven-it-plugin-expression</artifactId>
         <version>2.1-SNAPSHOT</version>
         <executions>
           <execution>
-            <id>step 3</id>
+            <id>step 2</id>
             <goals>
-              <goal>reset</goal>
+              <goal>eval</goal>
             </goals>
             <phase>validate</phase>
             <configuration>
-              <logFile>target/step-3.properties</logFile>
+              <outputFile>target/step-2.properties</outputFile>
+              <expressions>
+                <expression>project/properties</expression>
+              </expressions>
             </configuration>
           </execution>
         </executions>