It looks like it has something to do with multiple accounts or an IP address being shared by other Bitcointalk users which is the consensus answer for the ones experiencing it.
can member login the same time with 2-3 different address? maybe someone out there has accessed my account while I am logged in.
I don't understand what has shared IP and etc. In the beginning, I never use real address while accessing the Internet because I ever read the news the hacker can easy hijacking computer activity using real IP.