<DefaultLayoutOverride> blocking shortcut creation

Question

When <DefaultLayoutOverride> or <DefaultLayoutOverride LayoutCustomizationRestrictionType="OnlySpecifiedGroups"> and </DefaultLayoutOverride> are added to the below xml file, the taskbar shortcut no longer appears, and the user is prevented from creating new start menu tile shortcuts (dragging and dropping). 

The start layout setting is configured with a user configured GPO (user config>Admin Templates>Start Menu and Taskbar>Start Layout). The goal is to add the shortcut (copied from a GPP) to the taskbar while still allowing additions to all shortcut locations (eg. start menu tiles, taskbar, etc.).

What am I missing?

<?xml version="1.0" encoding="utf-8"?>
<LayoutModificationTemplate
    xmlns="http://schemas.microsoft.com/Start/2014/LayoutModification"
    xmlns:defaultlayout="http://schemas.microsoft.com/Start/2014/FullDefaultLayout"
    xmlns:start="http://schemas.microsoft.com/Start/2014/StartLayout"
    xmlns:taskbar="http://schemas.microsoft.com/Start/2014/TaskbarLayout"
    Version="1">
<DefaultLayoutOverride>
  <CustomTaskbarLayoutCollection>
    <defaultlayout:TaskbarLayout>
      <taskbar:TaskbarPinList>
        <taskbar:DesktopApp DesktopApplicationLinkPath="%APPDATA%\Microsoft\Windows\Start Menu\shortcut.lnk" />
      </taskbar:TaskbarPinList>
    </defaultlayout:TaskbarLayout>
  </CustomTaskbarLayoutCollection>
</DefaultLayoutOverride>
</LayoutModificationTemplate>

Answer 1

I was able to get this to work by following the example at https://learn.microsoft.com/en-us/windows/configuration/configure-windows-10-taskbar#sample-taskbar-configuration-added-to-start-layout-xml-file

I also changed the below line to configure a partial start layout: https://learn.microsoft.com/en-us/windows/configuration/customize-and-export-start-layout#configure-a-partial-start-layout

<DefaultLayoutOverride LayoutCustomizationRestrictionType="OnlySpecifiedGroups">