Yea, I've noticed that too, but I thought it was due to running 2 different XF systems on the same domain and logging in and out between them with the same user.
Is this a particular version? If it's not something new to 1.2 (as in, you didn't have it in the exact same situation in 1.1), it's likely an IP issue (such as via CloudFlare). I still heavily suspect that it's the latter (and thus not a bug).
Yea, I've noticed that too, but I thought it was due to running 2 different XF systems on the same domain and logging in and out between them with the same user.
Is this a particular version? If it's not something new to 1.2 (as in, you didn't have it in the exact same situation in 1.1), it's likely an IP issue (such as via CloudFlare). I still heavily suspect that it's the latter (and thus not a bug).
You're right. You'd should probably change the cookie prefix.