I just hovered to the right of a comment to get the little "bookmark!" symbol, but nothing appeared? I'm on a desktop PC, have just changed recently to "sober workplace" - does that stop this feature working? The enable bookmarks thingy still says yes.
I just quickly switched to 'sober workplace' to test - and the bookmark function appears to be absent from it. I don't know whether that is purposeful or the usual 'unintended consequence of development'. You'll need a comment from a staffer on that one.