We have an MSI that has been created that simply copies some files to
the C: and edits HKLM on the registry. Theres nothing in the user hive
at all. The apps are user associated.

When a user logs onto a PC for the first time, the app installs via the
MSI and then executes the EXE. The next time the user logs on, the exe
is simply run as the application is already installed. This can be seen
in the diagnostics as it shows the application as installed.

When a second user logs into the PC, the first time they login and run
the app, it appears to reinstall or verify the MSI and then start the
exe file. On the second login, the exe simply starts straight away.

My question is, is this normal behaviour?

Or, is it a case that as the application was installed by User1, it
shouldnt try to reinstall/verify when User2 logs in?

I can see that when User2 logs in, the zen diagnostics show that the
application isnt installed, even though it is as a result of User1
installing the MSI on first run.