i m having similar issues with Yoast plugin, did this solved your problems ?
I asked for fix , but there is no reply...Basically
I found inside my webmaster tool,a huge number of duplicate title tags (1700) and meta description (1050)..
Basically, errors are showing /0/ at the end or sometimes the same title twice written
Screenshot : http://i43.tinypic.com/s26v87.jpg
So , do you think this would fix it ?