An odd little bug occurred In my game 'bring it on' on the high seas map, game # 35067.
I successfully attacked a city containing an enemy valkyrie and opted to raze it. The valkyrie was carrying a magic ring which ended up being dropped into a razed city square. When I tried to enter that square I got the message 'target has changed, click to confirm' or something along those lines. I clicked 'OK', but wasn't allowed to enter with any stacks. I exited the map, and re-entered, but the bug was still in effect. Eventually I re-built the city, and was able to enter the square normally.