I just got an updated version of the Miles & More app today (version 3.0.0, adjustments for iOS 11/iPhone X it seems), and while trying to sign in and using the built-in extension for 1Password it just dumps me out to the start screen of the app after 1Password scans my face.
I'm not sure if this is an issue with this specific app (it probably is, their quality usually isn't the greatest), the fact that I'm running iOS 11.2 Beta 2 or the 1Password beta itself.
Here's a screen capture of it: https://d.pr/FREE/lpZ943
1Password Version: 6.10 (61000010)
Extension Version: Not Provided
OS Version: iOS 11.2b2
Sync Type: Not Provided