Weird view behavior when an elevation and a transparent background color are used on API 21

Question

Using a background color for a view with some alpha (e.g. #99fe0038) and some elevation on API 21 reveals two circles: one for the view itself and another inside:

Elevation and background color are set via code:

view.setElevation(getResources().getDimensionPixelSize(R.dimen.fab_elevation_lollipop));
view.setBackgroundColor(Color.parseColor("#99fe0038"));

Without setting elevation everything looks like expected.

Is it an Android bug or have I missed something here?