diff --git a/src/wp-includes/pluggable.php b/src/wp-includes/pluggable.php
index da97b559cc..0b6771ab29 100644
--- a/src/wp-includes/pluggable.php
+++ b/src/wp-includes/pluggable.php
@@ -91,7 +91,6 @@ if ( ! function_exists( 'get_user_by' ) ) :
 	 *
 	 * @since 2.8.0
 	 * @since 4.4.0 Added 'ID' as an alias of 'id' for the `$field` parameter.
-	 * @since 5.8.0 Returns the global `$current_user` if it's the user being fetched.
 	 *
 	 * @global WP_User $current_user The current user object which holds the user data.
 	 *
@@ -100,18 +99,12 @@ if ( ! function_exists( 'get_user_by' ) ) :
 	 * @return WP_User|false WP_User object on success, false on failure.
 	 */
 	function get_user_by( $field, $value ) {
-		global $current_user;
-
 		$userdata = WP_User::get_data_by( $field, $value );
 
 		if ( ! $userdata ) {
 			return false;
 		}
 
-		if ( $current_user instanceof WP_User && $current_user->ID === (int) $userdata->ID ) {
-			return $current_user;
-		}
-
 		$user = new WP_User;
 		$user->init( $userdata );
 
diff --git a/src/wp-includes/user.php b/src/wp-includes/user.php
index 0511a8a890..08e13cdc0e 100644
--- a/src/wp-includes/user.php
+++ b/src/wp-includes/user.php
@@ -1854,15 +1854,10 @@ function update_user_caches( $user ) {
  *
  * @since 3.0.0
  * @since 4.4.0 'clean_user_cache' action was added.
- * @since 5.8.0 Refreshes the global user instance if cleaning the user cache for the current user.
- *
- * @global WP_User $current_user The current user object which holds the user data.
  *
  * @param WP_User|int $user User object or ID to be cleaned from the cache
  */
 function clean_user_cache( $user ) {
-	global $current_user;
-
 	if ( is_numeric( $user ) ) {
 		$user = new WP_User( $user );
 	}
@@ -1885,13 +1880,6 @@ function clean_user_cache( $user ) {
 	 * @param WP_User $user    User object.
 	 */
 	do_action( 'clean_user_cache', $user->ID, $user );
-
-	// Refresh the global user instance if the cleaning current user.
-	if ( get_current_user_id() === (int) $user->ID ) {
-		$user_id      = (int) $user->ID;
-		$current_user = null;
-		wp_set_current_user( $user_id, '' );
-	}
 }
 
 /**
diff --git a/tests/phpunit/tests/pluggable.php b/tests/phpunit/tests/pluggable.php
index b6ac4a87b1..5bde2deb06 100644
--- a/tests/phpunit/tests/pluggable.php
+++ b/tests/phpunit/tests/pluggable.php
@@ -339,19 +339,4 @@ class Tests_Pluggable extends WP_UnitTestCase {
 		return $signatures;
 	}
 
-	/**
-	 * @ticket 28020
-	 */
-	public function test_get_user_by_should_return_same_instance_as_wp_get_current_user() {
-		// Create a test user.
-		$new_user = self::factory()->user->create( array( 'role' => 'subscriber' ) );
-
-		// Set the test user as the current user.
-		$current_user = wp_set_current_user( $new_user );
-
-		// Get the test user using get_user_by().
-		$from_get_user_by = get_user_by( 'id', $new_user );
-
-		$this->assertSame( $current_user, $from_get_user_by );
-	}
 }