Cannot build CN Tower: BNW bug?

[I.T.]

So, I'm playing as Venice, Commerce/Tradition/Freedom sp trees.

Finally researched CN tower - and then I find I can't build it.

Weird. Is there some SP condition for building it, like order? Nothing in the help--

Here's the save file:

Apologies if there's already a thread, but couldn't find one..

 

[FeiLing]

Chances are very high that either it was been build already by someone in the game or that you are currently building it in one of your cities (maybe only put it in a building queue by accident), which makes it unavailable in all other cities of yours.

 

[I.T.]

I'm playing as Venice. So there is only one building queue. Puppets never build wonders, right?

And Sejong hasn't got the tower listed. I don't think he even has it researched.

 

[I.T.]

Seems that reloading has fixed it.

But seriously, it's a pretty simple game, how come it can have such weird bugs?

 

[I.T.]

Tried replaying from an older save, but no bug.

So reloading fixed it. But it did happen. I was beelining for the tower to get the last few SP's out of the way, and then when I couldn't build it, I was exasperated.