Nested animation leads to selector prefixes in front of "from" and "to

[saranrapjs]

Using from and to in a CSS animation that's nested doesn't seem to work. EG the following scss:

.custom-selector {

& {
  color:blue;
}
@keyframes zoomer {
  from {
    transform:scale(0.5);
  }

  to {
    transform:scale(1);
  }
}

}

...input and expected/correct result:
http://sassmeister.com/gist/55b3686b7599bd810187

...scssphp incorrect result:

.custom-selector {
  color: blue; }

@-webkit-keyframes zoomer {
  .custom-selector from {
    transform: scale(0.5); }

  .custom-selector to {
    transform: scale(1); } }
@keyframes zoomer {
  from {
    transform: scale(0.5); }

  to {
    transform: scale(1); } }

(using 0.1.6)