Show an installed app's icon in Launchpad

I recently installed an app called NetLogo. I installed it via Homebrew Cask by running:

brew cask install netlogo

The app installation created a folder in /Applications directory. It comes with 5 .app bundles as shown:

The most used app out of the 5 is the one named NetLogo 6.1.0.app (second row, second last item from right). However, the icon for it doesn't show up in Launchpad. The icons for the other 4 showed up in Launchpad normally after the installation.

I can search for and launch the app fine using Spotlight.

Later I moved the 4 app icons in a Launchpad folder named NetLogo.

What could possibly be preventing NetLogo 6.1.0.app icon from appearing in Launchpad, and how can I make it show up? I have tried reinstalling by running:

brew cask zap netlogo

followed by

brew cask install netlogo.

I am running macOS Mojave 10.14.6.

To add an icon/app to Launchpad, you can simply drag it to the Launchpad icon.