Are you testing this in the Editor or in a packaged build?
You shouldn’t have to clear the Standalone flag to make this work. But you also can’t do this sort of testing in the Editor because it does all sort of things to preload and keep loaded certain assets based on what you might be working on. If the only reason it’s still loaded is the Standalone flag, it sounds like you’re doing this in Editor and if that’s the only reason it’s loaded you’re fine. Just don’t clear it as part of your own implementation.