It would appear something has broken with Apple Login through Firebase, specifically in Safari and only on iOS 16.4 and above. All other browsers (that don't use Safari webview) work just fine. The native app implementation of Firebase also works just fine.
Unfortunately, there seems to be no meaningful way to debug this, and Google has yet to get back to me. Considering Apple Login is still working below iOS 16.4, I don't think the problem is on my end. The logs we get indicate the login completed successfully, but never actually does.
We're also hearing from our other teams that Apple Login is also broken in Facebook SDK, an on the exact same device/browser combinations.
First, has anyone else encountered this? Second, is there a way I can get better logs from Apple Login on my devices?