Upgraded to 2.8.4 and tags dont work

I upgraded to WP 2.8.4 and now i cannot post tags. I can make a post but the tags will not stay once added. It will let me add them but once i save draft or publish they go away. On occasion maybe one out of 50 will stick. I have removed all plugins and theme and it still does it. I reuploaded the wp-includes and wp-admin folders and nothing changed. Tried changing out the JS for an old one, i have tried 50 different things i have found on the forum and nothing has worked.