Just a note to see if anyone is experiencing similar. In the last 48 hours or so the ads on my site have switched from being perfectly targetted on each page as 'Subject A-G' to suddenly being all 'Subject A', making them meaningless to any of my traffic other than those Subject A types.
I can temporarily force them to be on the point by adding a query string?subect B, so the ads are still there.. Just there seems to have been a switch somewhere to a 'site category' match instead of a 'page category' match.