I tried again and i can see that it works second time....the first click on the topic title thinks about it for a while and then underlines it without actually opening the thread. If you then click it when it's underlined then it does open....
However i think on the ipad the thread never opens it just goes round and round underlining it - I'll check again later.
Do the thread links open on first click for you?
Hmm ok for me on iphone 1st click on post link does nothing but underline it, 2nd click then opens it - annoying but it works.
On ipad, no amoint of clicking opens the link but if you keep your finger on the link and wait for the popup and then click open it does go in.
So both are usable - just not that friendly.
Maybe next iOS version will update safari and fix this. Closing question for now.