goodroi - 12:23 pm on Mar 12, 2013 (gmt 0)
Welcome to WebmasterWorld!
For a long time Google has been rewriting title tags for their serps. They typically do this to make the results more relevant to the user.
If you are trying to diagnose a drop in traffic to your website I would not worry about Google rewriting your title tag. I would look at if your title tag was good for a user and not just over optimized for SEO.