The Wall Street Journal got its hands on a document Intel was sharing with some of its customers (see note below), in which it advised them to "delay additional deployments of these microcode updates." Stephen Smith, Intel's data-center group general manager, told the publication that the bugs didn't have anything to do with security and that the document was being shared with computer makers and large cloud providers. Since the Wall Street Journal published its report, Intel has released a blog post explaining the systems affected by the reboots are running Broadwell and Haswell CPUs. "We are working quickly with these customers to understand, diagnose and address this reboot issue," it said.
Microsoft also halted some of its updates earlier this week after some AMD computer users reported that they couldn't boot their computers after installing its patch. And Intel reported that most people would experience a small amount of slowdown -- less than 10 percent -- on their personal computers after installing its fix.
One of Intel's partners told the Wall Street Journal that only telling some of its customers about the issue was a bad move on the part of Intel, saying the public has "been given the microcode update but has not been given the important technical information that Intel recommends that you don't use this." But security researcher Paul Kocher, who discovered some of the issues with Intel's chips, said this sort of thing is to be expected. "It doesn't surprise me a lot that there would be some hiccups."
Update: While the Wall Street Journal reported that only some of Intel's customers were receiving notice that they may want to hold off on installing its updates, Intel tells us that all of its customers were notified. The notice "was sent to all customers through the standard patch notification process," a spokesperson told us.