collapsing toolbar layout won't collapse

I have a collapsing toolbar layout that has 2 issues with it:

1) it is static and does not collapse and I can't find the reason why

2) the last row in the recyclerview is being shown half way offscreen, I think it should be fixed one the collapsing is fixed?

XML code:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Controllers.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/AppBarLayout"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_scrollFlags="scroll|snap|exitUntilCollapsed"
            app:contentScrim="@color/colorPrimary"
            app:title="Hero Title">

            <ImageView
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="#000000" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Hero Title"
                android:textStyle="bold"
                android:textSize="20dp"
                android:textColor="#ffffff"/>

            <android.support.v7.widget.Toolbar
                android:layout_width="match_parent"
                android:layout_height="150dp"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Dark">

            </android.support.v7.widget.Toolbar>

        </android.support.design.widget.CollapsingToolbarLayout>

    </android.support.design.widget.AppBarLayout>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/herosRecyclerView"
        android:layout_width="395dp"
        android:layout_height="715dp"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"/>
</android.support.design.widget.CoordinatorLayout>

and here is an image of what I mean by half offscreen:

https://i.sstatic.net/c5lq2.jpg

Please try this. It will work.

<?xml version="1.0" encoding="utf-8"?>
    <android.support.design.widget.CoordinatorLayout 
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/colorWhite"
        tools:context=".Controllers.MainActivity">

        <android.support.design.widget.AppBarLayout
            android:id="@+id/AppBarLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

            <android.support.design.widget.CollapsingToolbarLayout
                android:layout_width="match_parent"
                android:layout_height="150dp"
                android:textAlignment="center"
                app:contentScrim="@color/colorPrimary"
                app:layout_scrollFlags="scroll|exitUntilCollapsed"
                app:title="Hero Title">

                <ImageView
                    android:layout_width="match_parent"
                    android:layout_height="150dp"
                    android:background="#000000"
                    app:layout_collapseMode="parallax"
                    app:layout_collapseParallaxMultiplier="0.7" />

                <android.support.v7.widget.Toolbar
                    android:layout_width="match_parent"
                    android:layout_height="?attr/actionBarSize"
                    app:layout_collapseMode="pin"
                    app:popupTheme="@style/ThemeOverlay.AppCompat.Dark">

                </android.support.v7.widget.Toolbar>

            </android.support.design.widget.CollapsingToolbarLayout>

        </android.support.design.widget.AppBarLayout>

        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

            <android.support.v7.widget.RecyclerView
                android:id="@+id/herosRecyclerView"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />
        </FrameLayout>

    </android.support.design.widget.CoordinatorLayout>