Have you seen this on other machines or just your own? It might be something related to your setup.
If you open the Font Book application on your mac and look down the list of fonts (particularly at Helvetica, Arial etc - the common ones) you might see some with dots next to the font name. If that's the case:
Select the font by clicking the name, then click 'resolve duplicates' in the edit menu
That fixed an issue with certain fonts on my machine a while back.