Which is a dumb policy for security patches. When its fixed it should be released.
> If Google isn't willing to wait the two additional days such that the patch can be deployed within the regular update window, this means that Google effectively gives MS only 60 days to react and fix issues (because once they missed the second patch day, the vulnerability will be disclosed before the third).
Google doesn't dictate Microsoft's patch releasing policy. 90 days are 90 days. Microsoft doesn't have "only 60 days", they have 90 days like anyone else, and they chose to miss it by adhering to a policy of their own choosing that makes security patches less timely.
The whole purpose of a fixed 90-day window is to give reasonable time to fix a security vulnerability but also to create pressure to do so timely. Making exceptions for vendors to accommodate existing policies that make security fixes less timely would both increase the effort for Google (as a fixed time window is always easier to implement than one that varies with each vendors policies) and undermine the whole purpose of the 90-day timeline.