hiddenusers options does not always hide user

I use the plugin on an customers site to display all members.
I used the option ‘hiddenuser=myusername’ (where myusername = my admin account name) to hide my own account as I’m not part of the community.

THis works well if a user just visits the memberpage. But as they browse through it my account picture suddenly appears when they go back to page 0.

http://ww.wp.xz.cn/extend/plugins/author-avatars/