windows 10 chrome before you ask :)
when I flip a thread it isn't going to the last post on the thread, it's going (I think) to the top of the last page. And sometimes landing in the middle of a page. It's very weird.
If I refresh a flipped thread, it goes totally off piste and could end up on a different page altogether but not the first or last page.
Could you get your tech folks to have a rummage in your back end and see ?