Super Fighting Workers Glitch

[Narnia]

I was invading one of my neighbor. I attacked and conquered on of her cities and then when I ended my turn the game notified me that I had also conquered another city. I had no military presence anywhere near that city and when I looked, it still had several ENEMY troops there and the only troops that belonged to me were two worker units! I am NOT using a mod. Does anyone have the faintest idea what just happened?
My game was prepatched to whatever civ4 complete is patched to (I forgot what patch it is)

 

[The_J]

Yap, and that's one patch to less .
That bug was fixed i thought in 3.17, but obviously not, please install the patch 3.19, then it will be fixed.