How can I change compiling rule less to css?

I have in my less file line like this:

.icon-enter {
  width: 22px;
  height: 18px;
  background: url('data:image/svg+xml;...') no-repeat;
  background-size: 100%;
}

But after it would be compiled I have result:

.icon-enter {
  width: 22px;
  height: 18px;
  background: url('data:image/svg+xml;...') 0 0/100% no-repeat;
}

So it's work fine in new Chrome. But in Android Stock Browser on Android 4.1 icon doesn't apear. If I add background-size: 100% in css and remove it from background then it will work fine in Android 4.1.

I use Ember.js and ember-cli and addon ember-cli-less. Can I change rule of compiling for background-size?