1. Unrecognized attribute error.
Whenever Google Shopping is showing the error: Unrecognized attribute from your feed, please be sure that your uploading the right type of Feed during uploading your Feed to your Google Merchant Account.
Since March 2015 Google Shopping has a new type of feed named "Online Product Inventory Update" which can be used to just update the Google Shopping items but you don't have to use it combined with this extension as your feed would be automaticly updated by Google.
So whenever you get this error, change the Feed Type to products instead of Online Product Inventory Update.