You can try some tricks from here https://appletoolbox.com/2016/11/macos-app-store-updates-not-showing-ghost-fix/ https://appletoolbox.com/2016/11/macos-app-sto

You can try some tricks from here https://appletoolbox.com/2016/11/macos-app-store-updates-not-showing-ghost-fix/ https://appletoolbox.com/2016/11/macos-app-store-updates-not.... Namely, try going to System Preferences -> App Store and press Check Now.