Permanent ban doesn't seem to be working

We are getting several hundred emails saying an IP address has been permanently banned corresponding to an equal number of entries in the log. Why would we receive so many notifications about an IP address being permanently banned? By definition you would assume we would receive just one. We have changed our setting to digest email but the notifications keep flooding in. Any help is much appreciated and thanks for creating such a great security plugin!

https://www.ads-software.com/plugins/better-wp-security/