Very strange VPN experiment result...

I've been trying out free VPNs lately, and decided to experiment with Hotspot Shield and Cyberghost. First, I started Hotspot shield and noted the IP they gave me. While that was running, I decided to run Cyberghost at the same time, noting my IP--just to see what would happen. I then checked my IP and geolocation at auditmypc.com.

Now here's the strange part. My IP address was neither the one Cyberghost gave me, nor the one Hotspot Shield gave me, and it wasn't my real IP either. It did show a geolocation, but no server ID. It seems as if I was assigned some random IP from who knows where! I checked it at a couple other IP checking sites, and the same thing happened. None of them could ID the server I was on. The whole deal lasted about 5 minutes, then Cyberghost "locked" my internet connection and made me restart. Anyone have any idea where I could have gotten that unknown IP from, or what may have happened?