Windows Icon Caching
In some cases, this issue occurs because of Windows icon caching.
This issue may usually be resolved by rebooting your PC but if you wish to clear your PC's icon cache and see the correct icon without a reboot, please execute the following in your Windows command prompt:
Please refer to following article for more information:
Less relevant to your specific case, but for users with similar issues, often times compiling the standalone on an older version of Windows and running it on Windows 10, the icon does not show up. The simple solution is to compile your distributed application on the Windows 10 machine.
Attach Custom Icon in Windows Properties
One possible workaround is using attaching your custom icon in Windows Properties after compilation. A good guide on accomplishing this can be found here: