Show it's fixed via emberjs/ember-cli-babel#420

Author: chriskrycho

ember-cli-build.js

@@ -4,7 +4,9 @@ const EmberApp = require('ember-cli/lib/broccoli/ember-app');
 
 module.exports = function (defaults) {
   let app = new EmberApp(defaults, {
-    // Add options here
+    // babel: {
+    // debug: true,
+    // },
   });
 
   // Use `app.import` to add additional libraries to the generated

package.json

@@ -32,7 +32,7 @@
     "ember-auto-import": "^1.11.3",
     "ember-cli": "~3.28.4",
     "ember-cli-app-version": "^5.0.0",
-    "ember-cli-babel": "^7.26.6",
+    "ember-cli-babel": "chriskrycho/ember-cli-babel#e1c6b60",
     "ember-cli-dependency-checker": "^3.2.0",
     "ember-cli-htmlbars": "^5.7.1",
     "ember-cli-inject-live-reload": "^2.1.0",
@@ -58,8 +58,7 @@
     "npm-run-all": "^4.1.5",
     "prettier": "^2.3.2",
     "qunit": "^2.16.0",
-    "qunit-dom": "^1.6.0",
-    "tracked-built-ins": "^2.0.0"
+    "qunit-dom": "^1.6.0"
   },
   "engines": {
     "node": "12.* || 14.* || >= 16"