[quote='868376022, DTS Engineer, /thread/809171?answerId=868376022#868376022']
To be clear, you specifically meant:
/Applications
...not the standard Applications directory? That's not actually one of our standard directories, which opens the possibility that the system "missed" the existence of the app, so it wasn't registered with LaunchServices.
[/quote]
The Launch Services Programming Guide says that
A built-in background tool, run whenever the system is booted or a new user logs in, automatically searches the Applications folders in the system, network, local, and user domains and registers any new applications it finds there.
The one in the user domain is ~/Applications. Also note that the Finder gives that one the standard Applications icon, whereas if you create an Applications folder in some random location, it gets a generic folder icon. So at least by some measures it is one of your standard directories.
I'll see if I can replicate in a VM.