The main upgrade issue seems to be a lack of accessibility permissions (even though they are apparently ticked). The primary symptom is typically not being able to type keys from Keyboard Maestro (ibncluding Command-C/V for Copy/Paste actions). Things to try include:
- Toggle the Accessibility permissions for Keyboard Maestro and Keyboard Maestro Engine off and on again.
- Restart
- Quit and Relaunch the Keyboard Maestro Engine
- Quit Keyboard Maestro and Keyboard Maestro Engine and run the Terminal command “tccutil reset Accessibility” and relaunch Keyboard Maestro.