We have been moved by our host Communiteq to V2.8 and something strange is happeniing that I cannot figure out. Before the change, read topics were shaded light grey while unresad topics .were black. Since the change read topics no longer become grey so no one can see what has been read vs unread. Does anyone have any idea why this is the case or have any suggestion to fix the issue. A similar thing is seen with the dark theme where read topics remain bright white
Hard to say without seeing your forum with our own eyes.
Did you try deactivating your custom themes/components with https://your-discourse.com/safe-mode and then navigate yourself to see if the issue persists?