Then the issue is, it picks you up through your IP.
If you log in from somewhere else, your IP is logged twice.
Meaning you will appear on it twice.
Just a guess, but pretty logical.
This time you're right Campbell, but you're right when you say it happens all the time. Sometimes a user can be on 8-9 times repetitively. The plugin just does that sometimes. It's something we can't control.