diff --git a/mapper/src/test/java/tw/com/softleader/data/jpa/spec/NestedSpecificationResolverTest.java b/mapper/src/test/java/tw/com/softleader/data/jpa/spec/NestedSpecificationResolverTest.java
index ff62406..3bb85b2 100644
--- a/mapper/src/test/java/tw/com/softleader/data/jpa/spec/NestedSpecificationResolverTest.java
+++ b/mapper/src/test/java/tw/com/softleader/data/jpa/spec/NestedSpecificationResolverTest.java
@@ -111,7 +111,10 @@ void allAnd() {
             .extracting("specs", LIST)
             .hasSize(2);
     depth1.first().isInstanceOf(Equals.class);
-    depth1
+    var depth2 =
+        depth1.element(1).isInstanceOf(Conjunction.class).extracting("specs", LIST).hasSize(2);
+    depth2.first().isInstanceOf(Equals.class);
+    depth2
         .element(1)
         .isInstanceOf(Conjunction.class)
         .extracting("specs", LIST)
@@ -389,7 +392,7 @@ public static class NestedAnd {
   @AllArgsConstructor
   public static class NestedInNestedAnd {
 
-    @NestedSpec String name;
+    @Spec String name;
   }
 
   @Builder
diff --git a/mapper/src/test/java/tw/com/softleader/data/jpa/spec/ReflectionDatabindTest.java b/mapper/src/test/java/tw/com/softleader/data/jpa/spec/ReflectionDatabindTest.java
index 1fff467..180ba22 100644
--- a/mapper/src/test/java/tw/com/softleader/data/jpa/spec/ReflectionDatabindTest.java
+++ b/mapper/src/test/java/tw/com/softleader/data/jpa/spec/ReflectionDatabindTest.java
@@ -29,6 +29,7 @@
 import java.util.Collection;
 import java.util.Optional;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.CyclicBarrier;
 import lombok.AllArgsConstructor;
 import lombok.SneakyThrows;
 import org.junit.jupiter.api.Test;
@@ -49,17 +50,28 @@ void fireOnlyOnce() {
 
     assertThat(databind).hasSize(5);
 
-    var numberOfThreads = 1;
+    // Release every thread at the same instant so multiple threads race into
+    // getFieldValue() on the *same* Databind instances and genuinely contend on
+    // the AtomicBoolean CAS + CountDownLatch dedup.
+    var numberOfThreads = 32;
     var service = newFixedThreadPool(numberOfThreads);
-    var latch = new CountDownLatch(numberOfThreads);
+    var startBarrier = new CyclicBarrier(numberOfThreads);
+    var done = new CountDownLatch(numberOfThreads);
     for (int i = 0; i < numberOfThreads; i++) {
       service.submit(
           () -> {
-            databind.forEach(Databind::getFieldValue);
-            latch.countDown();
+            try {
+              startBarrier.await();
+              databind.forEach(Databind::getFieldValue);
+            } catch (Exception e) {
+              throw new RuntimeException(e);
+            } finally {
+              done.countDown();
+            }
           });
     }
-    latch.await();
+    done.await();
+    service.shutdown();
 
     databind.forEach(
         bind -> {