Feed blank after upgrading to 3.5.1

Figured it out… the plugin ‘Advanced Permalinks’ was the conflict. I turned it off and the feed worked immediately.

I was waiting for a response and read this sticky post at:
https://www.ads-software.com/support/topic/troubleshooting-wordpress-35-master-list?replies=4

I noticed it listed that plugin. Hope this helps someone else.