Safari losing Facebook login

Well, I know there seem to be several topics discussing Safari loosing cookies but my issue seems to be different. I lose my Facebook login within second of logging in. Somewhere between 15-60 seconds I am logged back out of Facebook.

I can confirm that this is unique to Safari as I'm happily on Firefox right now with no problems... but the scrolling is much nicer in Safari and Firefox seems to not like three-finger-back-and-forward surfing.

Any thoughts on why this would be happening? My logins for other sites are unaffected and I reinstalled Safari from the Apple installation... So I don't know what else to do to "reset" Safari.

Thanks for any tips.