Global keystroke captures being swallowed up by 1Password 8 Beta ?

This sounds like secure input blocking 3rd party keyboard listeners.

1Password enables secure input when entering information into 1Password -- much like the system does for password fields.

It's easy to introduce a bug where secure input is enabled but never disabled. If this happens, then quitting 1Password will restore normal input. Typically, we will only enable secure input when the 1Password window has keyboard focus.

This will prevent some applications like TextExpander from working in 1Password. But it should not effect other "global keyboard shortcuts" in other applications.

I'm not sure what mechanism hammerspoon is using, but it sounds like it's being blocked.

Here is something you can do to test this assumption...

Open Terminal.app
From the Terminal menu, choose "Secure Keyboard Entry".

Now try, your hammer spoon keystroke and see if it is blocked.