Still my first game.  After yonks of building and no AI aggro, I go looking for trouble.  I'm at war with some guy --- good.  I hover over an output of his, sword icon, march there, poof, it's mine.  Great!  But now what?  My attempts to stomp on him are in vain.  I can no longer "attack" anything of his.  If I send my guys against, say, a city of his, they end up marching on the spot just outside the city!  They won't attack --- nor outposts etc.  After a number of turns, thankfully I seem able to attack him again.  We never declared peace throughout.

Anyone else?  I assume this is a (bad) bug?  It's a bit disconcerting 'coz it's my first game, and I wondered if somehow I wasn't supposed to be able to attack, but now I think it was just nonsense?

Tx.