Social.localUser.Authenticate prompt called every time app gets focus

Hi, I'm on macOS 10.14 and have encountered this issue in both Unity 2018.4.11f1 and 2019.3.0f5. Once I have called Social.localUser.Authenticate, the login prompt comes up. Irrespective of how I proceed (cancelling or authenticating), when I change focus from the window and then return, the prompt comes up again. Is this the intended behavior? If so, is there a way to suppress future popups?

Additionally, the first prompt ("currently signed in to...") that comes up seems to be linked to the iCloud account, not the Game Center account. This seems incorrect, to me, as these need not match (why is Unity even looking at iCloud credentials for this?). It also seems to be caching this information somewhere, as the prompt is showing an iCloud account that I am not currently signed in to.

In general, I'm just very boggled by the behavior I'm seeing. Any info to demystify this would be greatly appreciated! Thanks.