If they had come forward and said so, we wouldn't be asking here. As the OP said, there was absolutely zero communication on this. ATT, MSFT, WP, Samsung support reps just refuse to answer the question on Twitter. Shame on MSFT.
Blame Samsung for switching the hardware on MS and not telling them. If MS can update all the devices from htc, LG and even the troublesome dell with few issues that should tell you the problem is with Samsung not microsoft.
well when every one else got mango , they still said early to mid november. it was posted in an article on engaget and on wpcentral.