Maybe...

kptdobe · kptdobe · commit d330ced03cc4 · 2018-08-15T11:31:06.000+02:00
diff --git a/src/FirebaseArduino.cpp b/src/FirebaseArduino.cpp
@@ -179,7 +179,9 @@ FirebaseObject FirebaseArduino::readEvent() {
   String event = client->readStringUntil('\n').substring(6);
   client->readStringUntil('\n'); // consume separator
   FirebaseObject obj = FirebaseObject(event.c_str());
-  obj.getJsonVariant().asObject().set("type", type);
+  if (NULL != type) {
+    obj.getJsonVariant().as<JsonObject&>().set("type", type);
+  }
   return obj;
 }
 
