Safari not filling in all remembered passwords

[hazmat]

I save a lot of login passwords through Safari. I find that some web sites consistently do not get my password filled in. I've tried deleting those sites and making it ask me again, but the same behavior happens again. Every once in a while the password will all of a sudden come in, but then not work after that again. I saw the Keychain First Aid utility and ran it, but it said mine was fine.

Any ideas?

Thanks.