I don't know if it's a bug or it was intentional, but you can buy Modernism upgrades without unlocking Modernism first.
Upgrades for Modernism appear right after unlocking Renaissance. Normally you cannot upgrade something You haven't unlocked first, right?
Cannot reproduce the problem, since I already finished the simulation.
Beta 24_27
Simulation: Visual
#Modernism bug?
pliant vessel
serene rivet
You can do this with Rennaisance as well, as in the upgrades can be bought without unlocking the generator
pliant vessel
Still not fixed