I have a floating action button anchored to the bottom right of a coordinator layout. It is 16dp from the margins of the view (the margins are included by default and specif
The problem is a parent clipping the shadow. Look for the parent that is clipping the shadow (is not necessarily the next in the hierarchy) and add this to the view in the xml.
android:clipChildren="false"
I've been testing this right now removing and adding that line to the parent that was clipping the view and is working fine.
Adding another containers or changing the margins is a workaround that I don't recommend. It's too patchy. The mini fabs have different container sizes and require different sizes depending on the API level (<21 or >=21).