We've confirmed the bug with development and are working on addressing the issue. It's on the to-do list for fixes - please bear with, and pardon our dust during this phase of the transition to the new platform. And thanks for the heads-up on this!
Is it possible to mark threads in a section as read which are not tracked (either with a blue or red flag)? ie. The same functionality as the old forum had with the "Reset discussion tracking -> on new topics" link.