Cannon towers not working

[Widowmaker94]

So, like, playing the Renaissance campaign (haven't touched the other ones yet), I got cannon towers on one of my settlements, which is great, except...

they don't show up.

I have process_cq'd on an old siege save because the actual relevant one (It was a citadel, this is a city. But I needed to set this up quick to show what I mean)

Here's the ballista tower:

Ballista towers

Then I upgrade and this happens:

broken cannon towers

Is this Working As Designed for Sicilian Vespers 3.3, or is it a bug?

[Widowmaker94]

Apparently they are supposed to look like that? Neat.

But still, the cannon towers weren't working, even when folks were theoretically in range. No boom sound effect. No peeps being killed.