This has reared it's ugly head again. Using Safari (not mobile skin) on ipad air.
It has been happening for the past few days on about half the threads I visit. After clicking on 'New posts' from the blue bar, then clicking the 'view first unread' triangle next to the applicable thread from the full list of threads, it takes me either to the top of some random page or to the very first post in the entire thread. This is despite my having visited the thread many times before. I have to scroll all the way to the end to get to the latest, unread post. Same issue as reported before.

I can give you thread examples if you need them.