I bet someone at IBM found a bug, traced it back to some quirk in Windows that was hard/impossible to work around and the ticket got the attention of an engineer who figured out how to fix it in less than an hour. They decided the change was benign so they did it, commented it for posterity, and moved on.

Microsoft actually has a reasonably close relationship with large companies that develop on their platform. eg, their plug fests for devs to come put their stuff onto the same machine and see how they all inter operate on new versions of Windows. I used to work semi-closely with someone doing Windows driver work. He knew a lot of quirks in the platform and even could escalate to the point of getting help from kernel engineers.