Customers Can't add comments when the "In Progress" catagory

[Puppa Smurf]

For some reason our customers can no longer leave comments if the status moves to a status that has the catagory "In Progress" attached to it.. e.g:

This appears to be on all status's not just the above. 

[Puppa Smurf]

This also happens when you paste a link for a number to another ticket. 

[Puppa Smurf]

Even odder, is that in the customer portal. If i go into a ticket with this status the comment bar isnt there, however  then I press "back" in my browser to go back, then go back into the same ticket, the comment bar is there.