I have Xcode 12 as a VPP app assigned via Apple School Manager to our Jamf Pro server
Just rebuilt a machine and tried installing Xcode and it looks to install but finishes way too quickly and doesn't install. No message of a failure and nothing in the Jamf inventory for the machine. Lots of other VPP apps are installing - Pages, Numbers, Keynote
Apart from downloading it direct, are there any other ideas of things to check?
I have just opened a ticket regarding this these are the errors I have found:
Error installing content: Xcode
com.apple.xpc.launchd: Coalition Cache Hit: app<application.com.apple.dt.Xcode.22961078.23627245(503)> 
com.apple.xpc.launchd (application.com.apple.dt.Xcode.22961078.23627245): Service exited due to SIGABRT
com.apple.xpc.launchd (application.com.apple.dt.Xcode.22961078.23627245): Service exited due to SIGTERM | sent by Dock
Not to sure what they mean, waiting until they get back to me
There are many threads out there on challenges installing Xcode esp via VPP where due to its size some kind of timeout or download interrupt occurs. In my org we've had better success grabbing the xip from the Apple developer site and redistributing / unpacking that to clients. Not pretty, very space consuming (you'll want upwards of 40GB free just in case) and manage users' expectations to have a LOT of patience.