diff --git a/.vscode/launch.json b/.vscode/launch.json
index 77330e222..2e724d08b 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -46,9 +46,9 @@
     {
       "type": "node",
       "request": "launch",
-      "name": "Build fastboot-app",
-      "program": "${workspaceFolder}/node_modules/.bin/ember",
-      "cwd": "${workspaceFolder}/test-packages/fastboot-app",
+      "name": "Build sample",
+      "program": "/Users/edward/hacking/sample/node_modules/.bin/ember",
+      "cwd": "/Users/edward/hacking/sample",
       "args": ["build"],
       "env": {
         "JOBS": "1"
diff --git a/packages/webpack/src/ember-webpack.ts b/packages/webpack/src/ember-webpack.ts
index 05739b959..0ad42979d 100644
--- a/packages/webpack/src/ember-webpack.ts
+++ b/packages/webpack/src/ember-webpack.ts
@@ -497,8 +497,12 @@ function babelLoaderOptions(majorVersion: 6 | 7, variant: Variant, appBabelConfi
     }
     // webpack uses acorn and acorn doesn't parse these features yet, so we
     // always tranpile them away regardless of what preset-env is doing
-    options.plugins.push(require.resolve('@babel/plugin-proposal-optional-chaining'));
-    options.plugins.push(require.resolve('@babel/plugin-proposal-nullish-coalescing-operator'));
+    if (!options.plugins.some(pluginMatches(/@babel\/plugin-proposal-optional-chaining/))) {
+      options.plugins.push(require.resolve('@babel/plugin-proposal-optional-chaining'));
+    }
+    if (!options.plugins.some(pluginMatches(/@babel\/plugin-proposal-nullish-coalescing-operator/))) {
+      options.plugins.push(require.resolve('@babel/plugin-proposal-nullish-coalescing-operator'));
+    }
   }
   return {
     loader: majorVersion === 6 ? 'babel-loader-7' : 'babel-loader-8',
@@ -506,4 +510,10 @@ function babelLoaderOptions(majorVersion: 6 | 7, variant: Variant, appBabelConfi
   };
 }
 
+function pluginMatches(pattern: RegExp) {
+  return function(plugin: string | [string] | undefined) {
+    return plugin && pattern.test(Array.isArray(plugin) ? plugin[0] : plugin);
+  };
+}
+
 export { Webpack };