pTemplate not rendering in PrimeNG 16

Question

I'm using primeng version 16 for a project, and have noticed that PrimeTemplates don't seem to render properly. The problem occurs even if editing the demo code on stackblitz, so I assume it's something to do with how I'm creating the template rather than anything about the way my project is set up. A simple example:

<p-menu [model]="menuItems">
  <ng-template pTemplate="start">
    <h1>Hello, world!</h1>
  </ng-template>
</p-menu>

The above code should, to my understanding, produce a menu with header text saying "Hello, world!" at the top. It does not. The menu renders as normal without the header template. This also occurs if the ng-template isn't nested within the p-menu. I have imported the SharedModule that contains the PrimeTemplate class as well. Am I doing something wrong here, or is this a bug?