Index: src/wp-includes/functions.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- src/wp-includes/functions.php	(date 1567065163000)
+++ src/wp-includes/functions.php	(date 1567074607036)
@@ -163,8 +163,13 @@
  * @return string The date, translated if locale specifies it.
  */
 function date_i18n( $format, $timestamp_with_offset = false, $gmt = false ) {
+
+	$timestamp = $timestamp_with_offset;
+
 	// If timestamp is omitted it should be current time (summed with offset, unless `$gmt` is true).
-	$timestamp = $timestamp_with_offset ? $timestamp_with_offset : current_time( 'timestamp', $gmt );
+	if ( ! is_numeric( $timestamp ) ) {
+		$timestamp = current_time( 'timestamp', $gmt );
+	}
 
 	/*
 	 * This is a legacy implementation quirk that the returned timestamp is also with offset.
@@ -223,7 +228,7 @@
 function wp_date( $format, $timestamp = null, $timezone = null ) {
 	global $wp_locale;
 
-	if ( ! $timestamp ) {
+	if ( ! is_numeric( $timestamp ) ) {
 		$timestamp = time();
 	}