Month view not showing all rows

[rogan]

When I'm logged in as Admin only the first 2 rows of the month view are displayed (see screenshot). This issue started when I created a new user. The month view displays correctly when logged in with the new account. 

Does anyone have any pointers as to what may be causing this and how I can fix it?

Thanks in advance (:

[rogan]

UPDATE: So after playing around with this a bit, I have a little more information. It appears that only the most recently created account can see the month view calendar. The calendar only partially displays for any account that isn't the most recently created. Sometimes only the first row of the calendar shows, sometimes the first 2 rows shows. 

Changing the authentication order has no effect. Privilege sets have no effect

I'm still at a loss to what is causing this and how to fix it.