SOLVED!
I was going to wait a couple more days to make sure, but I am convinced that this is the proper solution. I am having zero problems here on Sunday the 21st after turning off that Settings -> Accounts -> Sign-In Options -> "Use my sign-in info to automatically
finish setting up my device after an update or restart" option when magnificent Jean-YvesR posted it. The bug has not appeared since I turned it off.
I was convinced this was a bug, because it started after the 1709 update.
Now the question is, will Microsoft recognize this as a real bug, or will their paid deniers on these Forums keep blaming the Users? I am sick of this pattern of MS blaming Users for their poor coding, and it is time for Microsoft to clean up their act.
Microsoft, all you have to do on the next update is set the default for the button to OFF. It is a quick, simple fix that affects nothing. If you are willing to do the right thing, of course, then get rid of this useless setting, so that it stops being a
problem. I'm thinking you won't do the right thing, because that is becoming more and more rare in your company, at least since Nadella took over.
I have been a Microsoft man since I wrote batch files for DOS in the 1980's, so I am not some newbie blaming MS for everything. I am seeing a pattern of thinking by MS that appears to be "the customer is an idiot and we are the Gods now" and it is ruining
your wonderful company.
Quit it.
Joel.