I've seen a few cases of this, it seems to be a weird corruption in the 1Password third-party integration files.
In 1Password, turn off the integration in the Advanced settings:
That should resolve the issue.
If you have already moved to 1Password 8, the option isn't there. You can use 1Password 7 to turn it off, or you'll need to ask 1Password support how to turn it off if you no longer have it.
You should then be able to turn the integration back on and I believe that will rebuild the integration files without the corruption.
The next version of Keyboard Maestro should have some mitigation for this, avoiding 1Password entirely if you do not use the action.