Re: Cannot reproduce the net share issue...
I rather suspect that Microsoft is mucking around in SMB again, probably in an attempt to rearchitect/reengineer it yet again. You should, operative word should there, need to only step back and let a couple of months go by only, operative word only there, if you've completely screwed up and can't fall back as some other team(s) have made the new requirements irreversible. Network plumbing changes like these are very fussy. Notice, too, that Windows 8.1U1 and older don't seem to be affected. Maybe?Hopefully?
That's my view of what probably happened, although I can say it's happened to me on several occasions, for instance, having to go in manually and transform all the databases due to enterprise guys making a mandatory breaking change without inserting code to do the transform due to that breaking change by hand. Not fun!
 That's where I learned COBOL the hard way. By reading their source code and mentally making the transforms from prior to new. Sweet thing about COBOL, it's very verbose, and I liked it!
[2} The Harris system engineer gave me my own system GENTAP with all their compilers, tools and, especially, the damed man pages.
 God(s) bless some IBM system engineers who didn't mind taking a snot-nosed kid under their wing, who liked to hang around the computing center, and taught him to think this way when it's all FUBAR.