Google fonts URL break HTML5 Validation on w3.org

I load 3 fonts in different sizes using this HTML tag:

<link rel="stylesheet" type="text/css" href="http://fonts.googleapis.com/css?family=Open+Sans:400,600,300,800,700,400italic|PT+Serif:400,400italic|Bree+Serif">

Till ~1/2 weeks ago this was supported by w3.org validator for HTML5; now it gives this error:

 Line 14, Column 163: Bad value http://fonts.googleapis.com/css?family=Open+Sans:400,600,300,800,700,400italic|PT+Serif:400,400italic|Bree+Serif for attribute href on element link: Illegal character in query: not a URL code point.

What's the things the W3C Markup Validator does not like now?

URL encode the | (pipe characters) in the href attribute (%7C):

<link rel="stylesheet" type="text/css" href="http://fonts.googleapis.com/css?family=Open+Sans:400,600,300,800,700,400italic%7CPT+Serif:400,400italic%7CBree+Serif">

There are 2 ways to fix this validation problem:

1. URL encode the | (vertical bar/line) character in the href attribute of the link element (as %7C) :

   <link rel="stylesheet" type="text/css" href="http://fonts.googleapis.com/css?family=Open+Sans:400,600,300,800,700,400italic%7CPT+Serif:400,400italic%7CBree+Serif">
   

2. Separate fonts inclusion with multiple link elements :

   <link rel="stylesheet" type="text/css" href="http://fonts.googleapis.com/css?family=Open+Sans:400,600,300,800,700,400italic">
   <link rel="stylesheet" type="text/css" href="http://fonts.googleapis.com/css?family=PT+Serif:400,400italic">
   <link rel="stylesheet" type="text/css" href="http://fonts.googleapis.com/css?family=Bree+Serif">