could be a you issue, but not sure what it is. i've never used the remember me button when logging in and i never get logged out of my accounts. i know this doesn't really help fix your issue, but it might be a problem with your browser/settings instead of it being a site issue?
have you updated the browser or switched to a new one since this problem has started?
have you updated the browser or switched to a new one since this problem has started?