We're 100% sure that this isn't a case of GPU drivers splitting the ubershaders into separate shader variants because they've determined only a few code paths are ever taken, so are heavily optimising those paths and ignoring all the others until right when they're used?
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 48GB
GPU: Radeon 7800 XT
CPU: AMD Ryzen 5900X
RAM: 48GB
GPU: Radeon 7800 XT