XML : Android drawable layer-list item size not working on API < 23

I have a calendar that should show small dots on days that have an event. I'm using a drawable that draws the small dots.

This works great on my Nexus device with android 6.0, but if i try it on a device with 5.0 installed, it does not work. The dot fills the entire container.

Attached is a screenshot of the bug. The two large blue circles should be 4px small dots.

  <layer-list xmlns:android="http://schemas.android.com/apk/res/android">      <item xmlns:android="http://schemas.android.com/apk/res/android" android:gravity="center_horizontal|center_vertical">          <shape android:shape="oval">              <size android:height="4dp" android:width="4dp" />              <solid android:color="@color/blue"/>          </shape>      </item>  </layer-list>