I can verify it, using AI2Offline and firebase component doesn't work. App crash
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
Reported also in AI2OFFLINE custom package name - #10 by Anke
Test project was created online http://ai2.appinventor.mit.edu/