What is causing desktop shield icon overlay on *SOME* desktops

问题

I have a C++ Builder/Delphi application. It has the following manifest embedded as a resource:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
  <assemblyIdentity type="win32"
                    processorArchitecture="*"
                    version="1.0.0.0"
                    name="Manufacturer.Division.MyName" />
  <description>MyName</description>
  <dependency>
    <dependentAssembly>
      <assemblyIdentity type="win32"
                        name="Microsoft.Windows.Common-Controls"
                        version="6.0.0.0"
                        processorArchitecture="*"
                        publicKeyToken="6595b64144ccf1df"
                        language="*" />
    </dependentAssembly>
  </dependency>
  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">
    <security>
      <requestedPrivileges>
        <requestedExecutionLevel level="asInvoker" uiAccess="false" />
      </requestedPrivileges>
    </security>
  </trustInfo>
  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
    <application>
      <supportedOS Id="{e2011457-1546-43c5-a5fe-008deee3d3f0}" /> <!-- Win Vista and Win Serv 2008    -->
      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}" /> <!-- Win 7     and Win Serv 2008 R2 -->
      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}" /> <!-- Win 8     and Win Serv 2012    -->
      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}" /> <!-- Win 8.1   and Win Serv 2012 R2 -->
    </application>
  </compatibility>
  <application xmlns="urn:schemas-microsoft-com:asm.v3">
    <windowsSettings>
      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">True/PM</dpiAware>
    </windowsSettings>
  </application>
</assembly>

The software does not utilize registry HKLM - only HKCU, and it reads/writes to %LocalAppData%. It does not require administrative privileges.

The requestedExecutionLevel is set to asInvoker as seen from above XML manifest so it should not show shield icon.

On some desktops the shield icon does not appear and on some it does - other programs do not show shield icon on the same desktop. What is possibly causing shield icon (and the annoying UAC prompt) for my application?

On all systems - the user type is Administrator and UAC is set to default level (on Windows 7 and 8) - so I really see no cause of shield to be shown only on some and not on all desktops.

What is different on these systems where the shield icon appears compared to the ones where shield icon is not present?