What version of Windows are you running? I was able to install Cache for Windows (x86-64) 2017.1 (Build 726U) Thu Dec 8 2016 22:41:57 EST on Windows 7 (Ensemble installation). It was an upgrade from a previous version. It would be worth looking at the Windows event log to see if there were errors in there. If you don't get an answer here quickly, I suggest opening up a WRC issue.

This means that the SuperServer spawned a child job to handle incoming connections (this is what happens when any incoming connection comes to the SuperServer). After this child job starts up, it tried to read the connection information from the client, but the message wasn't there. This could be caused either by a slow network or by something that's simply attempting to connect to the SuperServer but not actually making a real connection (possibly testing that port). I would take a look at that IP address (10.251.10.16) to see what that is. My best guess is it's some sort of monitoring software if all 4 servers report the same IP address in their errors. 

If all you're really looking to do is shut down the instance, you can do this with a $zf(-2) callout to the OS to call 'ccontrol stop <instance> quietly restart' (or 'ccontrol stopstart <instance>' if you are on Windows). Do not use $zf(-1) for this, as shutdown would wait for the $zf(-1) calling process until reaching the ShutdownTimeout value. See this doc for an example of using $zf(-2):

http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=...

One important question when investigating these types of problems: is it one process, a couple processes, or many processes making the majority of these entries? You can find this out by viewing the file, either in the Management Portal or via JRNDUMP. More frequently than not, it's simply one runaway process, and it's quite either to either just terminate it, or at least determine what it's doing by inspecting the process itself.