diff --git a/src/wp-includes/date.php b/src/wp-includes/date.php
index 99bbb4e012..2f30fd53f2 100644
--- a/src/wp-includes/date.php
+++ b/src/wp-includes/date.php
@@ -256,16 +256,12 @@ class WP_Date_Query {
 
 		if ( isset( $query['month'] ) && $value = $this->build_value( $compare, $query['month'] ) )
 			$where_parts[] = "MONTH( $column ) $compare $value";
-
-		// Legacy
-		if ( isset( $query['monthnum'] ) && $value = $this->build_value( $compare, $query['monthnum'] ) )
+		else if ( isset( $query['monthnum'] ) && $value = $this->build_value( $compare, $query['monthnum'] ) )
 			$where_parts[] = "MONTH( $column ) $compare $value";
 
 		if ( isset( $query['week'] ) && false !== ( $value = $this->build_value( $compare, $query['week'] ) ) )
 			$where_parts[] = _wp_mysql_week( $column ) . " $compare $value";
-
-		// Legacy
-		if ( isset( $query['w'] ) && false !== ( $value = $this->build_value( $compare, $query['w'] ) ) )
+		else if ( isset( $query['w'] ) && false !== ( $value = $this->build_value( $compare, $query['w'] ) ) )
 			$where_parts[] = _wp_mysql_week( $column ) . " $compare $value";
 
 		if ( isset( $query['dayofyear'] ) && $value = $this->build_value( $compare, $query['dayofyear'] ) )
diff --git a/tests/phpunit/tests/query/dateQuery.php b/tests/phpunit/tests/query/dateQuery.php
index 47cc71d563..5e456e5c5d 100644
--- a/tests/phpunit/tests/query/dateQuery.php
+++ b/tests/phpunit/tests/query/dateQuery.php
@@ -555,4 +555,49 @@ class Tests_Query_DateQuery extends WP_UnitTestCase {
 
 		$this->assertEquals( $expected_dates, wp_list_pluck( $posts, 'post_date' ) );
 	}
+
+	public function test_date_params_monthnum_m_duplicate() {
+		$posts = $this->_get_query_result( array(
+			'date_query' => array(
+				'month' => 5,
+				'monthnum' => 9
+			),
+		) );
+
+		$expected_dates = array(
+			'1972-05-24 14:53:45',
+			'2003-05-27 22:45:07',
+			'2004-05-22 12:34:12',
+			'2007-05-16 17:32:22',
+			'2025-05-20 10:13:01',
+		);
+
+		$this->assertEquals( $expected_dates, wp_list_pluck( $posts, 'post_date' ) );
+
+		$this->assertContains( "AND ( ( MONTH( post_date ) = 5 ) ) AND", $this->q->request );
+
+		$this->assertNotContains( "AND ( ( MONTH( post_date ) = 5 AND MONTH( post_date ) = 9 ) ) AND", $this->q->request );
+	}
+
+	public function test_date_params_week_w_duplicate() {
+		$posts = $this->_get_query_result( array(
+			'date_query' => array(
+				'week' => 21,
+				'w' => 22
+			),
+		) );
+
+		$expected_dates = array(
+			'1972-05-24 14:53:45',
+			'2004-05-22 12:34:12',
+			'2025-05-20 10:13:01',
+		);
+
+
+		$this->assertEquals( $expected_dates, wp_list_pluck( $posts, 'post_date' ) );
+
+		$this->assertContains( "AND ( ( WEEK( post_date, 1 ) = 21 ) ) AND", $this->q->request );
+
+		$this->assertNotContains( "AND ( ( WEEK( post_date, 1 ) = 21 AND WEEK( post_date, 1 ) = 22 ) ) AND", $this->q->request );
+	}
 }
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