Improvements will come, folks just need to be a little patient and keep in mind this is a community led effort and the software currently being used does not have all the same features, or behaves slightly differently on some aspects.
Unfortunately, clicking on the square takes you to the first post that still has the “unread” flag set, not the first unread post after what may be a long series of unread posts that you’ve actually read. The problem (seems to) come up when you’ve skimmed through the earlier contributions to a long thread too quickly — the read flag doesn’t get set.
Please note this is an observation, not a complaint. But I would love to see it sorted somewhere down the road — perhaps with a “mark all as read” button.
Agreed and that's why I wrote "usually" 😀 It's odd when I read to the end of a thread, then later click on the blue square and land a couple of pages back from the end.