In another thread I reported that I thought there had been a post about this issue but I have not been able to find it.
Whilst I am advised that Safari on a PC is not supported, Safari on a Mac is. You should therefore report this as a bug as I am not aware of any solution.
The more people who report a bug or request a feature, the more likely it is to be actioned. Please follow this link.
See www.grainge.org for RoboHelp and Authoring tips
I will file this as a bug with Adobe. Anyways, for the time being, I will remove the Related topics button from all the topics since a major chunk of our customers use Mac. However, this issue limits the use of the Related topics feature.