Sorry Labguy, I'm out of ideas on this one.
If it's still your ipad, the only thing I can suggest is completely clearing your cache/cookies and seeing if reloading the site fresh will help out.
I'm wondering if another site might be using a similar prefix for the cookies. If that's the case, you'd log in here just fine - browse to the other site which would overwrite the cookies, then come back here with an invalid cookie and have to re-establish your session.
It's a long shot, but worth looking into. I might be able to change them here to see if it does anything - but then everyone else will lose their persistent session