node.js filesystem mangles Cygwin drive name - node.js

Question

I recently installed Cygwin64 after using Cygwin32 for quite some time and I'm now having problems with one of our production scripts. Node.js's 'readFileSync' seems to be prepending the windows drive letter to the path and then failing to resolve - e.g. /cygdrive/c/foo becomes c:/cygdrive/c/foo.
I've found various mentions of similar issues online but so far I've been unable to resolve this problem. My co-worker has a seemingly identical setup and does not experience the problem.
Here it is in a nutshell -
$ cat filetest.js
var fs = require('fs');
function main(argv) {
console.log("fileName => ", argv[2]);
var data = fs.readFileSync(argv[2], 'utf8');
console.log("success");
}
main(process.argv);
$ s/node filetest.js filetest.js
fileName => filetest.js
success
$ ls -l /cygdrive/c/temp/Test.txt
----rwx---+ 1 bdodd Domain Users 14 Jun 3 14:12 /cygdrive/c/temp/Test.txt
$ s/node filetest.js /cygdrive/c/temp/Test.txt
fileName => /cygdrive/c/temp/Test.txt
fs.js:338
return binding.open(pathModule._makeLong(path), stringToFlags(flags), mode);
^
Error: ENOENT, no such file or directory 'C:\cygdrive\c\temp\Test.txt'
and just for completeness...
$ cat /etc/fstab
# /etc/fstab
#
# This file is read once by the first process in a Cygwin process tree.
# To pick up changes, restart all Cygwin processes. For a description
# see https://cygwin.com/cygwin-ug-net/using.html#mount-table
# This is default anyway:
none /cygdrive cygdrive binary,posix=0,user 0 0
$ cd /cygdrive/
$ ls -l
total 40
d---rwx---+ 1 NT SERVICE+TrustedInstaller NT SERVICE+TrustedInstaller 0 Jun 3 14:09 c
dr-xrwxr-x 1 Unknown+User Unix_Group+33 0 Apr 29 2014 u
Insight would be greatly appreciated. Thanks!