There are a bunch of reports in the Google Webmaster Help forum where people are saying they are receiving emails that their Google accounts are “no longer verified by Google” to access their Webmaster Tools login.

The message reads:

JohnMu from Google promised to look into the issue, he said:

Thanks for posting! I’ve passed this issue on to the team to look at. I’ll post as soon as I have more to share!

This does seem fairly wide spread, although I personally did not have an issue.

Forum discussion at Google Webmaster Help.