My best guess is that
Math.random() is broken on your system for some reason (bizarre as that sounds). This is the first report I’ve seen of anyone getting collisions.
node-uuid has a test harness that you can use to test the distribution of hex digits in that code.
If that looks okay then it’s not
Math.random(), so then try substituting the UUID implementation you’re using into the
uuid() method there and see if you still get good results.
[Update: Just saw Veselin’s report about the bug with
Math.random() at startup. Since the problem is only at startup, the
node-uuid test is unlikely to be useful. I’ll comment in more detail on the devoluk.com link.]