As it says really. When you click on the three dots at the bottom of any post and you get the drop-down menu, none of those options are working for me. It's particularly annoying as when I open a thread I've bookmarked, it doesn't automatically scroll to the last bookmarked post. Instead I have to scroll through till I find it. I was using 'bottom' to render this slightly less irritating but now even this doesn't work.
Bookmark appears to work but obviously if the thread doesn't open to your last bookmark then it's pretty pointless.
Sorry if I'm duplicating a known issue but as I can't navigate easily due to this very problem I hope you'll forgive me @MNHQ.
I'm using on Safari on iPhone, iOS up to date.