Background image in css not working in custom theme

I have a CSS file in mydomain.com/drupal/sites/all/themes/Mytheme/assets/css/style.css and images in mydomain.com/drupal/sites/all/themes/Mytheme/assets/images

In the style.css I have used the below code.

.class{
background-image: url(../images/star.png);
}

The Background image is working correctly when i disable the Advanced CSS/JS Aggregation module.

But when i enable the Advanced CSS/JS Aggregation the background image path is showing wrong path.

.class{
background-image: url(drupal/assets/images/star.png);
}

The Theme path is missing here.

Correct path should be

.class{
background-image: url(drupal/sites/all/themes/Mytheme/assets/images/star.png);
}