It was more common for commercial discs and some consumer discs to have the data layer sandwiched between the bottom surface and label layer, especially later in cd/dvd’s heyday, to prevent tiny scratches on the label or sharpie marks from destroying bits in the data layer.
Because Microsoft isn’t responsible for every program that runs on their OS.
CrowdStrike is an EDR that enterprises choose to install. The bug was caused by a dodgy content bundle update, which is something that’s meant to be 100% safe but evidently they found and triggered a bug.