Thanks for all the replies.
- I'm using the default vbulletin theme.
- Session timeout is set to 900. I believe that's the default.
- Users can view the site either
www.mysite or just the
http://mysite
I don't understand how it is just a handful of users having this issue.
I asked them to clear out their cookies/cache files and they still claim to have the issue.
I updated the usernames, checked if anything needed repairing, checked the settings on their account...
I'm too sure that this may be an issue on their side, but it's weird that 3 different people from various locations are having the same problem with my site.