diff --git a/components/camel-lumberjack/src/test/java/org/apache/camel/component/lumberjack/LumberjackComponentTest.java b/components/camel-lumberjack/src/test/java/org/apache/camel/component/lumberjack/LumberjackComponentTest.java
index 7c07fcfb4a9c3..30a05550b2c5c 100644
--- a/components/camel-lumberjack/src/test/java/org/apache/camel/component/lumberjack/LumberjackComponentTest.java
+++ b/components/camel-lumberjack/src/test/java/org/apache/camel/component/lumberjack/LumberjackComponentTest.java
@@ -26,9 +26,14 @@
 import org.apache.camel.test.junit5.CamelTestSupport;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.OS;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+@DisabledOnOs(value = { OS.LINUX },
+              architectures = { "s390x" },
+              disabledReason = "This test does not run reliably multiple platforms (see CAMEL-21438)")
 public class LumberjackComponentTest extends CamelTestSupport {
     private static int port;
 
diff --git a/components/camel-lumberjack/src/test/java/org/apache/camel/component/lumberjack/LumberjackMultiThreadIT.java b/components/camel-lumberjack/src/test/java/org/apache/camel/component/lumberjack/LumberjackMultiThreadIT.java
index bd35a5486ff3e..f5cf3a7a4de33 100644
--- a/components/camel-lumberjack/src/test/java/org/apache/camel/component/lumberjack/LumberjackMultiThreadIT.java
+++ b/components/camel-lumberjack/src/test/java/org/apache/camel/component/lumberjack/LumberjackMultiThreadIT.java
@@ -31,11 +31,16 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.OS;
 import org.junit.jupiter.api.parallel.Isolated;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+@DisabledOnOs(value = { OS.LINUX },
+              architectures = { "s390x" },
+              disabledReason = "This test does not run reliably multiple platforms (see CAMEL-21438)")
 @Isolated
 public class LumberjackMultiThreadIT extends CamelTestSupport {
 
diff --git a/core/camel-core/src/test/java/org/apache/camel/component/file/FileSortByIgnoreCaseExpressionTest.java b/core/camel-core/src/test/java/org/apache/camel/component/file/FileSortByIgnoreCaseExpressionTest.java
index 694be86b4b59e..6bc19c45f2179 100644
--- a/core/camel-core/src/test/java/org/apache/camel/component/file/FileSortByIgnoreCaseExpressionTest.java
+++ b/core/camel-core/src/test/java/org/apache/camel/component/file/FileSortByIgnoreCaseExpressionTest.java
@@ -21,10 +21,15 @@
 import org.apache.camel.builder.RouteBuilder;
 import org.apache.camel.component.mock.MockEndpoint;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.OS;
 
 /**
  * Unit test for the file sort by expression
  */
+@DisabledOnOs(value = { OS.LINUX },
+              architectures = { "ppc64le" },
+              disabledReason = "This test does not run reliably multiple platforms (see CAMEL-21438)")
 public class FileSortByIgnoreCaseExpressionTest extends ContextTestSupport {
 
     private void prepareFolder(String folder) {
diff --git a/core/camel-core/src/test/java/org/apache/camel/processor/ResequenceBatchNotIgnoreInvalidExchangesTest.java b/core/camel-core/src/test/java/org/apache/camel/processor/ResequenceBatchNotIgnoreInvalidExchangesTest.java
index 305e4253f10e3..44da90fbc93e4 100644
--- a/core/camel-core/src/test/java/org/apache/camel/processor/ResequenceBatchNotIgnoreInvalidExchangesTest.java
+++ b/core/camel-core/src/test/java/org/apache/camel/processor/ResequenceBatchNotIgnoreInvalidExchangesTest.java
@@ -17,10 +17,12 @@
 package org.apache.camel.processor;
 
 import org.apache.camel.builder.RouteBuilder;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.OS;
 
-/**
- *
- */
+@DisabledOnOs(value = { OS.LINUX },
+              architectures = { "s390x" },
+              disabledReason = "This test does not run reliably multiple platforms (see CAMEL-21438)")
 public class ResequenceBatchNotIgnoreInvalidExchangesTest extends ResequenceStreamNotIgnoreInvalidExchangesTest {
 
     @Override
diff --git a/core/camel-core/src/test/java/org/apache/camel/processor/ResequenceStreamRejectOldExchangesTest.java b/core/camel-core/src/test/java/org/apache/camel/processor/ResequenceStreamRejectOldExchangesTest.java
index fe8520d07b879..6731271190d9a 100644
--- a/core/camel-core/src/test/java/org/apache/camel/processor/ResequenceStreamRejectOldExchangesTest.java
+++ b/core/camel-core/src/test/java/org/apache/camel/processor/ResequenceStreamRejectOldExchangesTest.java
@@ -20,10 +20,12 @@
 import org.apache.camel.builder.RouteBuilder;
 import org.apache.camel.processor.resequencer.MessageRejectedException;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.OS;
 
-/**
- *
- */
+@DisabledOnOs(value = { OS.LINUX },
+              architectures = { "s390x" },
+              disabledReason = "This test does not run reliably multiple platforms (see CAMEL-21438)")
 public class ResequenceStreamRejectOldExchangesTest extends ContextTestSupport {
 
     @Test
diff --git a/core/camel-core/src/test/java/org/apache/camel/processor/StreamResequencerTest.java b/core/camel-core/src/test/java/org/apache/camel/processor/StreamResequencerTest.java
index 788caca70c8be..dc8e67672516c 100644
--- a/core/camel-core/src/test/java/org/apache/camel/processor/StreamResequencerTest.java
+++ b/core/camel-core/src/test/java/org/apache/camel/processor/StreamResequencerTest.java
@@ -32,10 +32,15 @@
 import org.apache.camel.processor.errorhandler.DefaultErrorHandler;
 import org.apache.camel.support.service.ServiceHelper;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.OS;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
+@DisabledOnOs(value = { OS.LINUX },
+              architectures = { "s390x" },
+              disabledReason = "This test does not run reliably multiple platforms (see CAMEL-21438)")
 public class StreamResequencerTest extends ContextTestSupport {
 
     protected void sendBodyAndHeader(String endpointUri, final Object body, final String headerName, final Object headerValue) {
diff --git a/core/camel-core/src/test/java/org/apache/camel/processor/ThreadsRejectedExecutionTest.java b/core/camel-core/src/test/java/org/apache/camel/processor/ThreadsRejectedExecutionTest.java
index 8c99be6ece66e..78839584924e2 100644
--- a/core/camel-core/src/test/java/org/apache/camel/processor/ThreadsRejectedExecutionTest.java
+++ b/core/camel-core/src/test/java/org/apache/camel/processor/ThreadsRejectedExecutionTest.java
@@ -27,10 +27,15 @@
 import org.apache.camel.component.mock.MockEndpoint;
 import org.apache.camel.util.concurrent.ThreadPoolRejectedPolicy;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.OS;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+@DisabledOnOs(value = { OS.LINUX },
+              architectures = { "s390x" },
+              disabledReason = "This test does not run reliably multiple platforms (see CAMEL-21438)")
 public class ThreadsRejectedExecutionTest extends ContextTestSupport {
 
     @Override