diff --git a/agents/common/src/main/java/com/dbx/agent/JdbcConnectionPoolRegistry.java b/agents/common/src/main/java/com/dbx/agent/JdbcConnectionPoolRegistry.java
index bf64bc995..57f7ca3d2 100644
--- a/agents/common/src/main/java/com/dbx/agent/JdbcConnectionPoolRegistry.java
+++ b/agents/common/src/main/java/com/dbx/agent/JdbcConnectionPoolRegistry.java
@@ -1475,7 +1475,7 @@ final class JdbcConnectionPoolRegistry implements AutoCloseable {
             call("physical_set_network_timeout", () -> {
                 connection.setNetworkTimeout(networkTimeoutExecutor, networkTimeoutMillis);
                 return null;
-            }, factoryDataSource, timeoutMillis);
+            }, factoryDataSource, timeoutMillis, true);
         }
 
         private <T> T call(
@@ -1483,6 +1483,16 @@ final class JdbcConnectionPoolRegistry implements AutoCloseable {
             PhysicalConnectionCall<T> call,
             ConnectionFactoryDataSource factoryDataSource,
             long timeoutMillis
+        ) throws SQLException {
+            return call(operation, call, factoryDataSource, timeoutMillis, false);
+        }
+
+        private <T> T call(
+            String operation,
+            PhysicalConnectionCall<T> call,
+            ConnectionFactoryDataSource factoryDataSource,
+            long timeoutMillis,
+            boolean preserveCompletedFailure
         ) throws SQLException {
             CompletableFuture<T> outcome = new CompletableFuture<>();
             try {
@@ -1511,6 +1521,13 @@ final class JdbcConnectionPoolRegistry implements AutoCloseable {
                 factoryDataSource.poison(failure);
                 throw failure;
             } catch (ExecutionException error) {
+                if (preserveCompletedFailure) {
+                    Throwable cause = error.getCause();
+                    if (cause instanceof SQLException sqlError) {
+                        throw sqlError;
+                    }
+                    throw new SQLException("JDBC physical operation failed: " + operation, cause);
+                }
                 SQLException failure = new PhysicalConnectionStateUnknownException(error.getCause());
                 factoryDataSource.poison(failure);
                 throw failure;
diff --git a/agents/common/src/test/java/com/dbx/agent/JdbcConnectionPoolingTest.java b/agents/common/src/test/java/com/dbx/agent/JdbcConnectionPoolingTest.java
index a4d16761f..dcc47ef8b 100644
--- a/agents/common/src/test/java/com/dbx/agent/JdbcConnectionPoolingTest.java
+++ b/agents/common/src/test/java/com/dbx/agent/JdbcConnectionPoolingTest.java
@@ -850,6 +850,27 @@ class JdbcConnectionPoolingTest {
         }
     }
 
+    @RepeatedTest(5)
+    void unsupportedNetworkTimeoutDoesNotPoisonIdentity() throws Exception {
+        AtomicInteger physicalOpens = new AtomicInteger();
+        String url = h2Url("unsupported_network_timeout");
+        try (Connection ignored = openH2(url, physicalOpens)) {
+            // Keep H2 bootstrap outside the setup classification watchdog.
+        }
+        physicalOpens.set(0);
+        try (JdbcConnectionPoolRegistry registry = new JdbcConnectionPoolRegistry(shortTimeoutPoolSettings(1, 32))) {
+            for (int attempt = 0; attempt < 2; attempt++) {
+                try (JdbcConnectionPoolRegistry.Lease lease = registry.borrow(
+                    "unsupported-network-timeout",
+                    () -> unsupportedNetworkTimeoutConnection(openH2(url, physicalOpens))
+                )) {
+                    assertTrue(lease.connection().isValid(1));
+                }
+            }
+            assertEquals(1, physicalOpens.get());
+        }
+    }
+
     @Test
     void blockedSetupAfterKnownFailurePoisonsCurrentAttemptGeneration() throws Exception {
         AtomicInteger connectionAttempts = new AtomicInteger();
@@ -2136,6 +2157,23 @@ class JdbcConnectionPoolingTest {
         );
     }
 
+    private static Connection unsupportedNetworkTimeoutConnection(Connection delegate) {
+        return (Connection) Proxy.newProxyInstance(
+            Connection.class.getClassLoader(),
+            new Class<?>[] {Connection.class},
+            (proxy, method, args) -> {
+                if ("setNetworkTimeout".equals(method.getName())) {
+                    throw new SQLException("Does not support setNetworkTimeout");
+                }
+                try {
+                    return method.invoke(delegate, args);
+                } catch (InvocationTargetException error) {
+                    throw error.getCause();
+                }
+            }
+        );
+    }
+
     private static Connection asynchronousAbortConnection(
         Connection delegate,
         CountDownLatch abortScheduled,