I just wonder if it is normal after you raze a city, and the message of partisans taking arms against you pop up, that sometimes these units don't appear on the map.
So bug or WAD?

I took a city, size 2, didn't raze it (honest!) and it self disbanded and I got a message that everyone had fled my army and taken up arms in Thebes against me.

I was like - wah!

this is actually an event so it doesn't always happen

Right. Some events are turned off before your game starts, to keep each game different, I suppose. It could probably be modded to be always on.

I was told that partisans were supposed to appear everytime you raze a city. Maybe this was changed in the final version.