I wanted to run a concordance with Xenophon's Historia (Loeb edition; just the first section). Something interesting happened.
It listed νυξ and Νυξ as separate entries, but showed the same results for both.

There were a few other words that showed this phenomenon.
Just for fun, I ran this on Anabasis 1.1, and it usually behaved correctly (for example, seeing Ἀρταξέρξης as a properly capitalized noun), but it sees Πόλις as a proper noun; yet, in this latter case, it does not repeat results with πόλις (lower case π).