About a week ago, we reported that Google AdWords accounts were hit with "Low Share of Voice" notices from Google. These notices appeared in their reports and it shocked and upset many advertisers who have been optimally running their campaigns for years.
After about a week or so of investigation by Google AdWords reps and engineers, Google has confirmed it was a reporting bug.
AdWordsPro Stephen told us yesterday:
I've asked for more information that I can share on this issue, but I wanted to update you immediately that the problem has been resolved. I want to reiterate that the labels had no effect on your performance, but you may have seen them if your campaign was experiencing a different issue that caused problems.
'Share of Voice' is still a part of AdWords, and these labels may appear in your account, but they should not be as common as they were during this period.
If you are still having issues, I would ask Stephen or the other Google reps in the Google AdWords Help thread.
Forum discussion at Google AdWords Help.