From the test account I see what you mean.
Are all your accounted named
user@server.domain.org or do most accounts use
user@domain.org?
Do you use domain wiki accounts at all or just global?
How many wiki@ accounts do you have?
zmprov gd domain.com | grep Notebook
Does it spit back that you have a domain level notebook?
zimbraNotebookAccount:
wiki@domain.com
ie is that account different than global level:
zmprov gacf | grep Notebook
You may need to fix the templates like:
zmprov in
wiki@domain.com
zmprov impn
wiki@domain.com /opt/zimbra/wiki/Template Template
Followed by:
zmmailboxdctl stop
zmmailboxdctl start
Clear your browser cache before checking again.
An ls -la on your /opt/zimbra/wiki/Template might also shed some light.