But we all tested that Microsoft patch before deploying it, right?
I give Microsoft the benefit of the doubt in this case that best to get a patch out for an actively exploited issue versus delaying it for a full integration testing cycle.
However Microsoft's QA for OS patches really seems to suck these days. Interesting insider view of why here:
The Windows 10 insider builds do include a "feedback hub" app to report bugs in the start menu, but it's non obvious, not on the desktop and unless you bother to search for how to report a bug you would probably never be aware of it.
I think if Microsoft added a one screen summary of how to report bugs on the insider build signup process and added some incentive for valid bugs such as Microsoft points or account credits this would cost them peanuts but massively improve the level of customer feedback.