you are trying to add a icon that has different colours to a FAB?
When doing that, make sure you add app:tint="@null". In your case the xml should look like this:
<com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton android:id="@+id/floating_btn_take_test" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="bottom|center" android:layout_marginBottom="@dimen/dimen_20dp" android:text="@string/txt_take_test" android:textColor="@color/primaryColor" app:backgroundTint="@color/color_white" app:elevation="@dimen/dimen_10dp" app:icon="@drawable/ic_color_icon" app:layout_anchorGravity="bottom|center" app:rippleColor="@color/secondaryColor" app:shapeAppearanceOverlay="@style/ShapeAppearance_Button" app:tint="@null" />