Since some recent forum change, any forum thread that was pinned at any time by a Blizzard employee or forum moderator keeps showing up at the top, even after being unpinned by the user. This is especially noticeable when a certain forum has quite some threads pinned, e.g. ~30 for Latest topics - Diablo IV Forums, and makes it really tedious to scroll to the actually active threads
For some threads, it might actually make sense to show up in this space, e.g. recent patch notes or important notices for the respective game, but some game forums even have “welcome threads” pinned, which usually only make sense to be read once and then unpinned