I'm on 3.5.1.18 Build 3.00.0200 and there are no updates available for it.
I found that adding
contentFrame.src = "copyright.html";
to the " // and the content div" section of webnav.js in the scripts folder
fixed this problem (where copyright.html is the name of a page in the help folder, but I'm not sure it has to be an actual file)
The only problem is webnav.js is overwritten every time I generate help. It's a pain since I have to add it manually every time I generate... I tried submitting the issue to support but I never heard back.