diff --git a/includes/engine/class-tmdo-entity-health.php b/includes/engine/class-tmdo-entity-health.php
index e470ef7..4a5278a 100644
--- a/includes/engine/class-tmdo-entity-health.php
+++ b/includes/engine/class-tmdo-entity-health.php
@@ -325,7 +325,20 @@ final class TMDO_Entity_Health {
 		return TMDO_Mode_Manager::ALL_MODES[ $idx - 1 ];
 	}
 
+	/**
+	 * Whether a backfill batch is scheduled for any group of the entity. Batches
+	 * are scheduled with (entity, group) args, so looking for (entity) alone
+	 * never found one (2.4.2 PR-137).
+	 *
+	 * @param string $entity_type Entity type.
+	 * @return bool
+	 */
 	private static function is_backfill_active( string $entity_type ): bool {
-		return (bool) wp_next_scheduled( 'wpdo_entity_backfill_batch', array( $entity_type ) );
+		foreach ( TMDO_Entity_Registry::get_groups_for_type( $entity_type ) as $group ) {
+			if ( wp_next_scheduled( 'wpdo_entity_backfill_batch', array( $entity_type, $group ) ) ) {
+				return true;
+			}
+		}
+		return false;
 	}
 }
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index c1fbd05..9e64583 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -180,7 +180,7 @@ if ( ! function_exists( 'do_action_ref_array' ) ) {
 	}
 }
 if ( ! function_exists( 'wp_next_scheduled' ) ) {
-	function wp_next_scheduled( string $hook ): int|false { return false; }
+	function wp_next_scheduled( string $hook, array $args = array() ): int|false { return $GLOBALS['_wp_next_scheduled'][ $hook ][ md5( serialize( $args ) ) ] ?? false; }
 }
 if ( ! function_exists( 'wp_schedule_event' ) ) {
 	function wp_schedule_event( int $t, string $r, string $h ): bool { return true; }
diff --git a/tests/unit/EntityHealthBackfillTest.php b/tests/unit/EntityHealthBackfillTest.php
new file mode 100644
index 0000000..bf071d2
--- /dev/null
+++ b/tests/unit/EntityHealthBackfillTest.php
@@ -0,0 +1,44 @@
+<?php
+declare(strict_types=1);
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Backfill batches are scheduled per (entity, group) — REST backfill and
+ * TMDO_Core re-chain `wpdo_entity_backfill_batch` with both args. The health
+ * panel looked for (entity) alone, never found a running backfill and kept
+ * offering to start one; starting one resets the group's checkpoint
+ * (2.4.2 PR-137, manual F-11).
+ */
+class EntityHealthBackfillTest extends TestCase {
+
+	protected function setUp(): void {
+		$GLOBALS['_wp_next_scheduled'] = array();
+		TMDO_Entity_Registry::init();
+		TMDO_Entity_Registry::register_adapter( 'user', new TMDO_Adapter_User() );
+		TMDO_Entity_Registry::register_group( 'user', 'eh_one', array( array( 'key' => 'eh_a', 'type' => 'text' ) ) );
+		TMDO_Entity_Registry::register_group( 'user', 'eh_two', array( array( 'key' => 'eh_b', 'type' => 'text' ) ) );
+	}
+
+	protected function tearDown(): void {
+		$GLOBALS['_wp_next_scheduled'] = array();
+		TMDO_Entity_Registry::init();
+	}
+
+	private function backfill_active( string $entity_type ): bool {
+		$m = new ReflectionMethod( TMDO_Entity_Health::class, 'is_backfill_active' );
+		$m->setAccessible( true );
+		return (bool) $m->invoke( null, $entity_type );
+	}
+
+	public function test_a_backfill_scheduled_for_one_group_is_seen(): void {
+		$GLOBALS['_wp_next_scheduled']['wpdo_entity_backfill_batch'][ md5( serialize( array( 'user', 'eh_two' ) ) ) ] = time() + 5;
+
+		$this->assertTrue( $this->backfill_active( 'user' ) );
+		$this->assertFalse( $this->backfill_active( 'post' ), 'other entities are not affected' );
+	}
+
+	public function test_no_scheduled_batch_means_no_backfill(): void {
+		$this->assertFalse( $this->backfill_active( 'user' ) );
+	}
+}