Difficulty with "Mark All Read" in the Forums

I've started experiencing difficulty with the Mark All Read button. I use the little bell (upper right) to look up new posts/comments, and I normally scrolled all the way down to the bottom to mark all posts as read. However, from yesterday, there are now two scroll bars (why?), and I have to keep remembering that it's the second bar that will give me the Mark All Read option.

But at least I still get the option from my laptop. When I access the forums from my mobile devices, I'm also no longer able to mark posts as read; the Mark All Read option shows up briefly at the top (maybe less than 5 seconds) and it doesn't show up again, even if I scroll all the way to the bottom (unless I go back to clicking on the bell … well, sometimes it works). This also started from yesterday.

Is anyone else experiencing this?