Same issue here "Before I show the code, one thing I have questioned is the fact that this game is still in development. In AppStoreConnect, the status of the leaderboard is "Not Live". Does this affect scores being posted?" I'd be curious too, especially because there is a "Delete test data" button as well with a description "After testing your leaderboards, you should remove the leaderboard test data before submitting the app for review." that suggest it should work before the app is sent to review. I'm using the class function version, no error returned, just silently nothing happens, no data in the leaderboard, neither in the Dasboard (triggered from tha Access Point) nor in AppStore Connect.

However, 15.0.1 has not yet, but Xcode 15.1.0 (22502) has solved this issue for me.

My app is not targeting yet the app store so i'm building using my Developer ID Application certificate I'm building now by xcode 13.2 a Unity 2021.1.28f1 produced xcodeproj on macOS 11.6.2 The produced app bundle is notarized during Archiving it and running seamlessly on macOS 11.6.2 even if no entitlements exception is used freezing on macOS 10.15.7 till the "Allow Unsigned Executable Memory" (com.apple.security.cs.allow-unsigned-executable-memory) entitlements is not added during the build So now the solution was for me to add com.apple.security.cs.allow-unsigned-executable-memory to the app entitlements

ok, one workaround for this https://github.com/w0lfschild/iTunesPlus/blob/master/iTunesPlus/iTunesPlus.mworks from catalina 10.15.2 beta2 (and still ok with beta3)