My Tokyo town skyscrapers will not finish

[Boxybrown11]

I’ve tried “finishing” several Tokyo town skyscrapers now (using 2 airport items expecting the next upgrade to require 3 airport items.) the buildings just again ask for 2 airport items and never upgrade to requiring 3 airport items. I’ve build mutable Tokyo town sky scrapers before and am level 65. Now not being able to “finish” these new Tokyo town skyscrapers is taking one of the last fun things for me to do in the game away.
Any help would be greatly appreciated
Thx

[varSollix]

TTZ buildings are very slow to upgrade overall. Make sure you have at least 3 specializations servicing the TTZ buildings you want to upgrade. TTZs seem very specialization hungry and I do notice that my specialization-heavy (5+) TTZ buildings look to upgrade a bit faster.