Universal Links / entry in Entitlements causes ApplicationVerificationFailed

Air 27 / iOS Debug/Standard -  (note: Ad Hoc builds but will not install on device)

If I comment out the following entitlement - all is well.

<key>com.apple.developer.associated-domains</key>

              <array>

               <string>applinks:www.mysiteurl.com</string>

  </array>

The appropriate "apple-app-site-association" file is accessible

This is the error when debugging - and the APP fails to install on device:

Error occurred while installing the application:

Installation Error: ApplicationVerificationFailed.

Logs reveal nothing more than the above