I haven't been able to determine exactly when this happens, but I've run into an issue where 1Password will cause Secure Input to be enabled, even after it's no longer active. (This would be mostly fine except it causes issues with programs like Keyboard Maestro and SteerMouse.)
I think it might start after filling on a webpage, when it prompts me to hit OK to fill the item? I'm not sure; I will update if I am able to figure it out any further.
1Password Version: 8.2.2
Extension Version: 2.1.3
OS Version: macOS 11.6