Codesigned and notorized app won't open unless dragged to another folder. Why?

Hi,

I'm at the the end of the whole codesign, notorize, staple deployment journey and testing the installation of my app that I've downloaded from Google Drive.

It is a zip file that contains just the app. When I double click to open, I get the "My App" is an app downloaded from the internet....prompt. It says it has checked it for malicious software and none has been detected.

When I click on Open, the app runs but the UI doesn't present - no windows are open. Quit doesn't work, I have to Force Quit.

If I drag it to another folder it opens OK. I realise that most third party apps have DMG installer, so the user has to drag the app as a matter of course, but I like the simplicity of using a .zip file.

I'd appreciate if someone could explain why this is happening (even after the user has granted approval to open) and if there is a way to open the app directly from where it has been downloaded to?

Thanks,

Stewart