I've had a problem with Blogger and OpenID; I'd just forgotten about it, because it's been a while since I got a Blogger account and started using that instead. What it's done with me is, when I fill in all the required fields and try to post the comment, refresh and leave the log-in fields empty as though I hadn't filled them in yet. No error message, just --- poof, data gone. Comment still there, but open ID and word verification data vanished.
I was using an LJ openID, so who knows, maybe blogger and LJ don't get along?
(And ironically, my browser lost contact with the LJ server the first time I tried to leave this comment.)