An authentication issue was addressed with improved state management. This issue is fixed in macOS Sonoma 14.1, iOS 17.1 and iPadOS 17.1. Photos in the Hidden Photos Album may be viewed without authentication.
https://support.apple.com/kb/HT213984
https://support.apple.com/kb/HT213982
https://support.apple.com/en-us/HT213984
https://support.apple.com/en-us/HT213982