Issues with logged IPs and users???

[RedGTiVR6]

I've just noticed a potential large issue on our forums.

I've had a post of mine deleted (I'm an admin). When I looked at the thread information by going to "Edit Thread", I noticed that it listed an IP address for our company. When I went to see what other users posted from that IP, I found a list of 90-something users. Many of these users aren't members of the company.

To boot, the IP that is posted is NOT our companies normal web access line.

I don't even know how to go about trouble shooting this.

I need to find out if this is a security issue, a plug-in gone wrong, etc.

Anyone able to point me in a direction?