Recently opened SamuraiSafe safes are listed under Recent in the Files app. The SamuraiSafe iCloud container is marked private, so this probably shouldn’t occur. Report filed with Apple.
On running an iPhone only app on an iPad, and using password autofill, a floating keyboard may be presented, and may be partially offscreen. Ensuring the keyboard isn’t floating before launching the app seems to help. Another workaround is to use SamuraiSafe cut/paste rather than autofill.