Currently the last visit info on 3.1 shows incorrectly. For example, earlier on AREA51:
Last visit was: Sun Nov 03, 2013 8:52 pm
I was on last night reading posts(Nov 7), and the moderator log shows I approved a post:
Tue Nov 05, 2013 11:33 am
After logging out via the logout link, and re-logging in it updates the last online info. Seems broken if your session just times out.