There are reports, and I have seen in some of my more convoluted accounts, a massive switch to the new Dashboard.
As a caution you might receive an email noting the following:
We’d like to inform you that Google Places no longer accommodates more than one authorized owner per business location. Your account contains one or more listings that have been identified as duplicates of other listings and as a result, some of the information you provide will not be shown to Google users anymore.
To get more information or request access to the other listings, please log into your Google Places account.
The Google Places Team
This can be caused by several factors:
1)The listing was claimed in some other dashboard long ago now forgotten
2)It is another dashboard and they got control
3)It was previously updated to Plus and Google didn’t reconcile the two listings. Brought both into your dashboard and is showing one as unverified.
There may be other use cases but these I think cover the common ones them