I'm also seeing sandboxed daemons behaving weirdly.
When calling
do {
try SMAppService.daemon(plistName: "com.example.daemon").register()
} catch let error {
[...]
}
the dialog in the right top corner saying Background Items Added and "Example App" added items that can run in the background for all users Do you want to allow this? appears.
Despite that, the register() method throws the
SMAppServiceDomain Code=1
error, which is operation not permitted.
Right after in the catch block, querying the .status of the daemon, I receive a value of 2, which corresponds to .requiresApproval.
I think this is a bug here, as the daemon's registration is successful, but the method still throws.