Total Administrators Spam

We are experiencing an issue where Ninjafirewall is sending a series of emails [NinjaFirewall] Alert: Database changes detected for administrator accounts. Within a few mins of each other we will receive multiple emails stating there are anywhere between 163 and 89 administrators and then a final email one that correctly states that there are only 12 administrators. Additionally, the email will list out multiple duplicate accounts that are not administrators at all. Any thoughts on what could be causing this issue?

Thanks in advance!