Windows 10 AppX apps may not inter-operate with AppV 5 apps as expected

Scenario

App-V package of software that used image file formats, copied the files to %TEMP% before using the prevailing FTA to launch the assigned app.  For operational reasons the %TEMP% folder in the App-V package needed to be virtualised.  In this case, on Windows 10, the application for displaying images was the built in AppX app "Photos". 

Fault

In the above scenario "Photos" was unable to display the image in the virtualised %TEMP% folder. It is theorized that the AppX app Photos was unable to "see" inside the App-V bubble as conventional apps can.

Workaround

If the user changed the FTA for the file extension to MSPaint (a conventional windows app) then paint would correctly launch, see the image file in the virtual %TEMP% folder and display it.