Css code in Quik CSS box changes in browser

I use the WPML plugin.
I added the same custom background-image in the “Quick CSS” box in the 3 languages to set a background image:

#wrap_all {
background:#666666;
background-attachment: scroll;
background-image: url(http://www.trijaxa.com/wp-content/uploads/2017/11/gradient-lichter.jpg);
background-repeat: repeat-x;
background-position: left top;
}
On the Dutch site the background image shows up. But in English and French not. When I inspect the code in the browser I see that the css-code for English and French is changed in:

background-image: url(‘http://www.trijaxa.com/wp-content/uploads/dynamic_avia/www.trijaxa.com/wp-content/uploads/2017/11/gradient-lichter.jpg’);

What’s wrong? And what can I do about this?

Kind regards Marijke