[Ken Case]

This has been happening for me for months as well, and when I get some spare cycles I'm planning to dive into the code to see if I can fix it.

I think the issue is related to an expired nonce when using digest authentication. OmniWeb fails its digest authentication attempt because its nonce has expired, and when it goes to regenerate its credentials it says "Oh, the last request for this URL failed; the login information must be wrong" and prompts for new information—rather than grabbing the perfectly valid information from the keychain. At least that's my theory, I haven't actually verified this in the code yet.