If you knew anything of the traditional release history for Microsoft you wouldn't have commented. All your post demonstrates is total ignorance of the context or history.

It was previously totally fine to use RCs for the last decade, probably way before that too, but I only have experience from then. RC in MS speak meant "pretty much finished, API won't change unless we find something desperately wrong".

Then it suddenly means basically pre-alpha, "anything can change, massively, between RC versions".