diff --git a/api_dev/src/main/java/com/google/appengine/tools/development/ApiProxyLocalImpl.java b/api_dev/src/main/java/com/google/appengine/tools/development/ApiProxyLocalImpl.java
index 900727db..9304d3b1 100644
--- a/api_dev/src/main/java/com/google/appengine/tools/development/ApiProxyLocalImpl.java
+++ b/api_dev/src/main/java/com/google/appengine/tools/development/ApiProxyLocalImpl.java
@@ -203,10 +203,12 @@ public Future<byte[]> makeAsyncCall(
     Semaphore semaphore = (Semaphore) environment.getAttributes().get(
         LocalEnvironment.API_CALL_SEMAPHORE);
     if (semaphore != null) {
-     // TODO: investigate why the acquire() locks when Sessions are configured in appengine-web.xml
-     // Maybe the semaphore has been released just before the app engine session manager starts
-     // saving the data in datastore.
-      semaphore.tryAcquire();
+      try {
+        semaphore.acquire();
+      } catch (InterruptedException ex) {
+        // We never do this, so just propagate it as a RuntimeException for now.
+        throw new RuntimeException("Interrupted while waiting on semaphore:", ex);
+      }
     }
     AsyncApiCall asyncApiCall =
         new AsyncApiCall(environment, packageName, methodName, requestBytes, semaphore);
diff --git a/pom.xml b/pom.xml
index 5c9bef72..ed3fb28a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -63,7 +63,7 @@
     <maven.compiler.target>1.8</maven.compiler.target>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <jetty.version>9.4.53.v20231009</jetty.version>
-    <jetty12.version>12.0.2</jetty12.version>
+    <jetty12.version>12.0.3</jetty12.version>
     <slf4j.version>2.0.9</slf4j.version>
     <distributionManagement.snapshot.url>https://oss.sonatype.org/content/repositories/google-snapshots/</distributionManagement.snapshot.url>
     <distributionManagement.snapshot.id>sonatype-nexus-snapshots</distributionManagement.snapshot.id>
diff --git a/runtime/local_jetty12_ee10/src/main/java/com/google/appengine/tools/development/jetty/ee10/JettyContainerService.java b/runtime/local_jetty12_ee10/src/main/java/com/google/appengine/tools/development/jetty/ee10/JettyContainerService.java
index 38660b73..b20ae2e9 100644
--- a/runtime/local_jetty12_ee10/src/main/java/com/google/appengine/tools/development/jetty/ee10/JettyContainerService.java
+++ b/runtime/local_jetty12_ee10/src/main/java/com/google/appengine/tools/development/jetty/ee10/JettyContainerService.java
@@ -57,6 +57,7 @@
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
@@ -70,6 +71,7 @@
 import org.eclipse.jetty.server.Handler;
 import org.eclipse.jetty.server.HttpConfiguration;
 import org.eclipse.jetty.server.HttpConnectionFactory;
+import org.eclipse.jetty.server.HttpStream;
 import org.eclipse.jetty.server.NetworkTrafficServerConnector;
 import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Response;
@@ -626,7 +628,20 @@ public boolean handle(Request request, Response response, Callback callback) thr
       // this and so the Environment has not yet been created.
       ApiProxy.Environment oldEnv = enterScope(request);
       try {
-        callback = Callback.from(callback, () -> onComplete(contextRequest));
+        request.addHttpStreamWrapper(s -> new HttpStream.Wrapper(s)
+        {
+          @Override
+          public void succeeded() {
+            onComplete(contextRequest);
+            super.succeeded();
+          }
+
+          @Override
+          public void failed(Throwable x) {
+            onComplete(contextRequest);
+            super.failed(x);
+          }
+        });
         return super.handle(request, response, callback);
       }
       finally {