Hello @octavo, Steam's shader pre-cache subcomponent feeds hardware independent shaders into your video driver to warm the video driver's on-disk shader cache. This subcomponent runs independently of Steam's download manager and isn't directly stopped by a game update. Also, a partially warmed on-disk shader precache isn't summarily discarded. Most if not all video drivers will use their on-disk shader cache to skip over shaders that are already there and ready.

Fossilize, the project that processes these hardware independent shaders may back off if it detects that the system is under disk I/O load to help the system stay responsive in general and Steam is supposed to stop background processing of the shader pre-cache when starting a game so that it does not adversely affect your game session.