Applications don't open on first click after macOS 27 "Golden Gate" update

Since this began after upGrading your MacBook Air to macOS 27.0, first determine whether the behaviour involves the pointing device, the Dock, or application launching.

Identify whether you are using the MacBook's built-in trackpad, an Apple Magic Mouse, an Apple Magic Trackpad, or a third-party mouse or trackpad. 

For an external device, note whether it uses Bluetooth, USB, or a hub/dock. 

If you normally use an external device, temporarily test with only the built-in trackpad. 

Apple provides the relevant mouse and trackpad settings in System Settings. Apple: Mouse settings on Mac

Determine whether all applications or only certain applications are affected. 

When testing, make one deliberate click and wait several seconds before clicking again. 

Also check whether the application is already running when the first click appears ineffective: a dot beneath its Dock icon indicates that it is open, and ⌘-Tab can be used to see whether the application is running.

Next, determine whether the behaviour occurs only when launching applications from the Dock. 

Test ordinary clicks in Finder, System Settings, and Safari, then launch the same application from Finder >> Applications. 

Apple documents both methods of opening applications. Apple: Open apps on Mac

If the behaviour occurs with the built-in trackpad and also outside the Dock, restart the Mac and test again. 

The key observations are which pointing device is involved, whether all or only some applications are affected, whether the application is already running, whether other macOS clicks respond normally, whether waiting after one click makes a difference, and whether Finder launches the application normally. 

These observations provide a clearer basis for determining the next troubleshooting step.