diff --git a/core-client/src/main/java/org/glassfish/jersey/client/ClientConfig.java b/core-client/src/main/java/org/glassfish/jersey/client/ClientConfig.java
index 53cc138518b..54cf97f9bd0 100644
--- a/core-client/src/main/java/org/glassfish/jersey/client/ClientConfig.java
+++ b/core-client/src/main/java/org/glassfish/jersey/client/ClientConfig.java
@@ -1,4 +1,5 @@
 /*
+ * Copyright (c) 2026 Contributors to the Eclipse Foundation
  * Copyright (c) 2012, 2024 Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018 Payara Foundation and/or its affiliates.
  *
@@ -425,12 +426,21 @@ private ClientRuntime initRuntime() {
 
             injectionManager.completeRegistration();
 
-            bootstrapConfigurators.forEach(configurator -> configurator.postInit(injectionManager, preInit.bootstrapBag));
+            bootstrapConfigurators.forEach(configurator -> {
+                if (!configurator.equals(preInit.clientComponentConfigurator)) {
+                    configurator.postInit(injectionManager, preInit.bootstrapBag);
+                }
+            });
+
 
             final ClientConfig configuration = new ClientConfig(runtimeCfgState);
             final Connector connector = connectorProvider.getConnector(client, configuration);
             final ClientRuntime crt = new ClientRuntime(configuration, connector, injectionManager, preInit.bootstrapBag);
 
+            // We call postInit here to clean up thread locals,
+            // while other configurators need to be postInit earlier because they set up dependencies for ClientRuntime
+            preInit.clientComponentConfigurator.postInit(injectionManager, preInit.bootstrapBag);
+
             client.registerShutdownHook(crt);
             preInit.messageBodyWorkersConfigurator.setClientRuntime(crt);
 
@@ -479,6 +489,7 @@ public int hashCode() {
         private final ClientBootstrapBag bootstrapBag;
         private final List<BootstrapConfigurator> bootstrapConfigurators;
         private final ClientMessageBodyFactory.MessageBodyWorkersConfigurator messageBodyWorkersConfigurator;
+        private final ClientComponentConfigurator clientComponentConfigurator;
 
         /* package */ PreInitialization(InjectionManager injectionManager) {
             this(new State(new JerseyClient()), injectionManager, null, null);
@@ -496,9 +507,9 @@ public int hashCode() {
             bootstrapBag.setManagedObjectsFinalizer(new ManagedObjectsFinalizer(injectionManager));
 
             messageBodyWorkersConfigurator = new ClientMessageBodyFactory.MessageBodyWorkersConfigurator(); // 2020
+            clientComponentConfigurator = new ClientComponentConfigurator();
 
-            bootstrapConfigurators = Arrays.asList(
-                    new RequestScope.RequestScopeConfigurator(),
+            bootstrapConfigurators = Arrays.asList(new RequestScope.RequestScopeConfigurator(),
                     new ParamConverterConfigurator(), // 2010
                     new ParameterUpdaterConfigurator(), // 2011
                     new RuntimeConfigConfigurator(runtimeCfgState), // 2012
@@ -507,7 +518,7 @@ public int hashCode() {
                     new ExceptionMapperFactory.ExceptionMappersConfigurator(), // 2015
                     new JaxrsProviders.ProvidersConfigurator(), // 2016
                     new AutoDiscoverableConfigurator(RuntimeType.CLIENT),
-                    new ClientComponentConfigurator(),
+                    clientComponentConfigurator,
                     new FeatureConfigurator(RuntimeType.CLIENT));
             bootstrapConfigurators.forEach(configurator -> configurator.init(injectionManager, bootstrapBag));
 
diff --git a/ext/cdi/jersey-cdi1x/src/main/java/org/glassfish/jersey/ext/cdi1x/internal/CdiComponentProvider.java b/ext/cdi/jersey-cdi1x/src/main/java/org/glassfish/jersey/ext/cdi1x/internal/CdiComponentProvider.java
index 4e3627bc816..95d85e6c555 100644
--- a/ext/cdi/jersey-cdi1x/src/main/java/org/glassfish/jersey/ext/cdi1x/internal/CdiComponentProvider.java
+++ b/ext/cdi/jersey-cdi1x/src/main/java/org/glassfish/jersey/ext/cdi1x/internal/CdiComponentProvider.java
@@ -1,4 +1,5 @@
 /*
+ * Copyright (c) 2026 Contributors to the Eclipse Foundation
  * Copyright (c) 2013, 2025 Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018, 2022 Payara Foundation and/or its affiliates. All rights reserved.
  *
@@ -145,6 +146,10 @@ public Boolean apply(final Class<?> clazz) {
 
     private boolean initialized = false;
 
+    // Shared by multiple clients, which can be initialized in parallel,
+    // therefore storing to a thread local and removing after initialization done in the done() method
+    private ThreadLocal<InjectionManager> effectiveInjectionManager = new ThreadLocal<>();
+
     public CdiComponentProvider() {
         customHk2TypesProvider = CdiUtil.lookupService(Hk2CustomBoundTypesProvider.class);
         injectionManagerStore = CdiUtil.createHk2InjectionManagerStore();
@@ -259,6 +264,14 @@ private boolean bind(final Class<?> clazz, final Set<Class<?>> providerContracts
 
     @Override
     public void done() {
+
+        if (beanManager != null) {
+            final CdiComponentProvider extension = beanManager.getExtension(CdiComponentProvider.class);
+            if (extension != null) {
+                extension.effectiveInjectionManager.remove();
+            }
+        }
+
         if (requestScopedComponents.size() > 0) {
             InstanceBinding<ForeignRequestScopeBridge> descriptor = Bindings
                     .service((ForeignRequestScopeBridge) () -> requestScopedComponents)
@@ -658,7 +671,6 @@ private StringBuilder listElements(final StringBuilder logMsgBuilder, final Coll
     /* package */ abstract class InjectionManagerInjectedCdiTarget implements InjectionManagerInjectedTarget {
 
         private final InjectionTarget delegate;
-        private volatile InjectionManager effectiveInjectionManager;
 
         public InjectionManagerInjectedCdiTarget(InjectionTarget delegate) {
             this.delegate = delegate;
@@ -671,7 +683,7 @@ public InjectionManagerInjectedCdiTarget(InjectionTarget delegate) {
         public void inject(final Object t, final CreationalContext cc) {
             InjectionManager injectingManager = getEffectiveInjectionManager();
             if (injectingManager == null || /* reload */ injectingManager.isShutdown()) {
-                injectingManager = effectiveInjectionManager;
+                injectingManager = effectiveInjectionManager.get();
                 threadInjectionManagers.set(injectingManager);
             }
 
@@ -706,7 +718,16 @@ public void dispose(final Object t) {
 
         @Override
         public void setInjectionManager(final InjectionManager injectionManager) {
-            this.effectiveInjectionManager = injectionManager;
+            // The injectionManager is always the same within a single invocation.
+            // We set it only once, which is a bit faster than calling set with the same value
+            final InjectionManager manager = effectiveInjectionManager.get();
+            if (manager == null) {
+                effectiveInjectionManager.set(injectionManager);
+            } else if (!manager.equals(injectionManager)) {
+                LOGGER.log(Level.SEVERE, "Leaking injection manager found in the current thread."
+                        + " Very likely because it wasn't removed in a previous invocation and"
+                        + " leaked into this invocation.");
+            }
         }
     }