This can happen for a few reasons, most commonly version mismatches. Your version of Ryujinx, the driver for your GPU, and the shader cache itself all need to be compatible.
If you notice flashing lights, missing textures, or strange colors, your cache might be misinterpreting a graphic instruction. Switching your Graphics Backend in Ryujinx settings from Vulkan to OpenGL (or vice versa), booting the game once, and switching back can sometimes flush out rendering bottlenecks. Step-by-Step Optimization Settings ryujinx shader caches
Compiled shaders contain proprietary code translated directly from the original game software. Distributing complete shader caches online occupies a legal grey area, which is why official emulation communities strictly forbid sharing them. This can happen for a few reasons, most