should be broken

components.minimal-repro\.hbs

{{#if this.hasBadge}}
	<p>Count is: {{this.totalBadgeCount}}</p>
{{/if}}

components.minimal-repro\.js

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';

export default class MinimalRepro extends Component {
  @tracked snazzy = false;
  
  get totalBadgeCount() {
    return this.args.data.reduce((count, item) => {
      if (item) {
        this.snazzy = true;
        return count + 1;
      }
      
      return count;
    }, 0);
  }

  get hasBadge() {
    return this.totalBadgeCount && this.snazzy;
  }
}

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  data = [true, false, true, false];
}

templates.application\.hbs

<p>Should be {{this.data.length}} items total.</p>
<MinimalRepro @data={{this.data}} />

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}