Checking our system logs I discovered that the Main Site Administrator account is resetting the passwords for the same 8 users every 3 minutes automatically. It looks like a system run process. 

I wanted to know:

1. Has this or something similar happened to anyone else?

2. What can we do to fix this error? My first thought is to discontinue the Site Admin account and set up a new one. 

3. What causes this type of thing and how can it be avoided in the future. 

Thank you for any assistance in this.