Font family CSS getting ignored after last update

In my own template I’ve the following CSS:

body {
	background: #ffffff;
	color: #222222;
	margin: 0;
	font-family: 'Open Sans', Arial, sans-serif;
	font-size: 9pt;
	line-height: 100%;
	letter-spacing: 1px;
}

Normally the CSS got applied to all elements in my invoice but after the last update some elements are not in this font anymore. I’ve no other font family settings in my CSS file. Can you may check this?