diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
index 8f540789c6..52e8fcf0cd 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
@@ -725,7 +725,10 @@ public function update_item( $request ) {
 			);
 		}
 
-		$owner_id = email_exists( $request['email'] );
+		$owner_id = false;
+		if ( is_string( $request['email'] ) ) {
+			$owner_id = email_exists( $request['email'] );
+		}
 
 		if ( $owner_id && $owner_id !== $id ) {
 			return new WP_Error(
diff --git a/wp-includes/version.php b/wp-includes/version.php
index df8735944f..ac1c76c24e 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-beta1-54316';
+$wp_version = '6.1-beta1-54317';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.