Windows 10 Anniversary Update came with a few unwelcome surprises for some users. The lockups, Kindle crashes and broken webcams are all thing we should probably have expected to be caught as part of internal testing the Insider program, but they obviously were not.
Windows has their own internal testers too, but apparently that staff has been cut quite a bit and Microsoft seems to be relying more on results from insiders (and probably Windows 10 telemetry information, I'm guessing).
Ars Technica has a great article on this, and bring up quite a few good points such as the fact that a lot of the Insider PCs are probably not being used as main PCs (which Microsoft does not encourage anyway), and therefore may not be used as much, or with all the peripherals that a main PC would be.
Whatever is going on, it's not the kind of quality that I think we should expect from a company of Microsoft's stature.