- Official Post
Sometimes it may happen that after you reinstall your Mac but don't recover a backup icons suddenly 2-3 times.
This is a known bug and can easily be fixed with a simple command.
Open the Terminal app and enter this
If this doesn't directly work you may switch off your Mac (REALLY SWITCH OFF) and wait for about 30 seconds. Than you can switch on again.
If that doesn't help you may really have multiple copies of the apps in your application folder.