Nah mate this is not about that. Outside belt armor should not effect internal citadel armor the way it does regardless if I even have a citadel tech which I don't in this case. I shouldn't get negative displacement for making my citadel bigger or in this case the entire length of the ship.
For some reason in the coding y'all have some weird link for aft forward armor ratioed in with main belt armor to cause bigger citadels to eventually have negative displacement. I am recommending you have citadel displacement completely seperate from main belt, aft forwad belt calculations.
Here are even more examples of this, this being a Spanish Dreanought hull 1 1905 shared design situatin and the other Japanese to also show that this is game wide.