Pogo has released a statement regarding the Message Center notification issue:
We’re aware of an issue where the Message Center notification indicator may remain visible even when there are no unread messages. This is a visual issue only and does not impact your account or gameplay. Our team is actively investigating the problem and working on a fix. Thank you for your patience while we resolve this issue.
We’ll be sure to keep you posted here when this issue has been resolved.
Thank you for letting us know