Since the last iOS update to 18.3.1 when a note is unlocked using FaceID or a passcode, it locks up again right away when you go to edit the note. If you force quit the app, the problem is solved temporarily. But then it returns.
If you open Bear's settings > Privacy and change the auto-lock notes after option do you experience the same issue?
No. Once I switched the delay to a new time it stopped.