The "Show 1Password mini" global shortcut - Command-Option-\ by default, though the bug still applies if you change it - doesn't work if you trigger it while menu bar auto-hiding is enabled, the menu bar is not visible, and a Chrome Incognito window is currently focused. 1Password mini does not show up, and if you later show the menu bar (e.g. by moving the cursor to the top of the screen), the 1Password Mini icon is highlighted blue, as if it's open. Clicking it de-highlights if, as it closing it, but at no point is the 1Password Mini window shown.
1Password Version: 1Password Version 6.8.8 (688001) Mac App Store
Extension Version: 126.96.36.199
OS Version: macOS 10.13.4 (17E202)
Sync Type: iCloud