Why would you think it's "working properly"?
The app somehow gained a permanent permission that I didn't give and that I can't remove no matter what I do. That's not working properly in any sense.
>I didn't give
This is not true, you do give consent when you pick a folder to open
It’s working properly in the sense that the Apple-provided file picker UI is designed to give permanent file permission access to an app. But the user thinks that access is temporary. It’s a mismatch between the user’s mental model and what’s actually happening.