Why do some city UI survive capture and not others?

[WillowBrook]

I captured a city with some colossal heads and the colossal heads remained. A while later in the game, I captured a city with some Alcazars, and they disappeared.

What's going on?

 

[BrotherInJah]

Colossal Head, come on how to move those in first place..

Jokes aside, have you been suzerain of CS atm of conquer? I'm guessing since I've never seen UI being left..