How is it not intentional? To me it seems very clear that someone designed this bot to specifically alter the LICENSE file so that it matches some sort of predefind Microsoft file.

Edit: To give a bit more nuance, I would guess that the actual bot changing the LICENSE files is not a mistake, but working as intended. What could, however, be a mistake is thinking that licenses can be legally overwritten. It wouldn't be a "rogue engineer" kind of mistake. Certainly several people at Microsoft have signed off on this.