I use the app Unlox which automatically locks my MacBook Pro's screen when I am away from the computer. After a recent BTT update, often when Unlox automatically locks my Mac, I lose keyboard shortcuts. There is some kind of notice in the BTT drop down menu that says there's a security issue. When I manually lock the computer and unlock it again everything works. It seems like BTT thinks locking the computer with a program like Unlox is a security risk. Other gestures seem to work, just not keyboard shortcuts. Maybe its a bluetooth issue since Unlox works with a bluetooth connection (to my phone so if my phone is too far away from the computer the Mac automatically locks).
BTT does not think that unlox is a security risk. This message means that some app has enabled „secure input mode“, which will prevent any other app from receiving keyboard input in the background. This is a macOS functionality and BTT just tells you when it has been enabled.
Only the app that has enabled secure input mode can disable it again.
The login screen usually enables this mode when it is activated, but disables it again when the login has finished. Maybe Unlox is doing something that breaks this?