I think I found code bug after trying again for a few hours. This will be my first commit. I submitted problem in Github too as not sure of process. Please double check my work though. Not sure if I should try to submit to zencart. The analytics problem from this is that it causes the brand name only for checked out items to be incorrect. All browsing experience on product pages will record brand properly. In reports though for checked out items in which someone wants to see total sales by brand name it will be incorrect.

Change line 217 of file in includes/classes/observers/class.ec_analytics.php

Change below code from "orders_products_id" to "products_id"
Code:
$brand = zen_get_products_manufacturers_name($items_in_cart->fields['orders_products_id']);