I believe the problem started on 10/13/12. The problem is tags do not appear in the post when the post is generated automatically with Wpematico
I tried with Auto-tag and Tag-Pig PLUGIN and the tags have stopped appering on the posts with both plugins around 10/13.
Wpematico plugin version 1.1.1
Auto-Tag version 0.5.1
Wordpress version 3.4.2
To get to tags to show up we have to resave the posts
Looks like a new wpematico was released around 10/13 which caused the problem