Use this.project.config over configCache

index.js

@@ -47,19 +47,14 @@ module.exports = {
   included() {
     this._super.included.apply(this, arguments);
 
-    const config = this.project.configCache;
     const env = this.app.env;
 
     // This configures EmberENV in a "hacky" way as the 'config' hook is called
     // before the options from EmberApp are provided. There currently is no way of handling
     // this case other than manually messing with configCache or modifing the dom by setting
     // up window.EmberENV before ember loads.
-    if (!config.get(env)) {
-      config.set(env, this.project.configWithoutCache(env));
-    }
-
     Object.keys(flagToEnvironment).forEach(flag => {
-      config.get(env).EmberENV[flagToEnvironment[flag]] = this.flagValue(flag);
+      this.project.config(env).EmberENV[flagToEnvironment[flag]] = this.flagValue(flag);
     });
 
     // Always register the version