Great catch @Saffith . I do believe that to be his issue after reading it. I have not experienced behavior like that on my mac at work but I don't download and run things out of Downloads often.
Quote:
The basic gist is that if you download and run a Gatekeeper app from the Downloads folder, the OS will copy the app into a read-only disk image and run it from there instead. See the link above for more details.