Oh no, nothing like that. In fact I've only found these "bad" keys in nostr.json files. If they showed up in events I would be getting deserialization errors all over the place. I really think it's just a mistake, someone mistyping their key, but I thought I would ask.

It was also news to me that the public key space isn't all of the 32-byte numbers, even though the private key space seems to be (all but the number zero).