Can't build Alloy Foundry and there is no reason why

[Qbix]

As you can see in the screenshot below, I don't have an alloy foundy built in that city yet I can't built one despite having a Titanium source in workable range. The advanced tooltip from the Enhanced User Interface mod even tells me the possible yield option but still, the building doesn't show up in the right panel.

I have already built one in another city and also received the quest from it.

Spoiler :

EDITH SAYS:

I improved the 2nd source of Titanium and voilà, now I can build the alloy foundry. What the actual...

Spoiler :

 

[Juanholio]

Is it a captured city? I had this scenario when I had two captured cities. I kept the first and razed the second because it was too close with valuable resources within the 3rd ring of the first city (I forget what the exact resource was but it was similar in that a building needed an improved workable tile).

When the 2nd city finshed razing the resource was in range of my city and within my borders but I couldn't build the linked building. Several turns later I could. I figured the second city 'owned' the tile and it took a little while for the first to culturally exapand enough to claim it even though my borders hadn't changed.

Can't tell if this is relevant to your situation but thought I'd mention it.