I waited, but seeing as how no-one is addressing the root problem, I can at least give you a work around that I use.
Using a browser with tab support, e.g. firefox, get the list of unreads, via the new link at the top or the menu, then middle click (or right click and select open in new tab) for each one you want to read, reply, whatever. Then close each as you are done with them, and your original list can't be hampered by DF forum bugs or anything else, 'cos you never needed to refresh it.
This method works reliably here now, but can cause flood protection trips on older DF sites if you are too quick, and their server is fast.
As you would appreciate, I read all posts - I don't open multiple windows, often refresh the current list, and rarely have the problem - it occurs on rare (maybe once a year) occasions when sessions have been reset from a server or PC hiccup, that's it.
Server specs (Server OS / Apache / MySQL / PHP / DragonflyCMS):
linux / apache 2.2.22 / mysqli 5.6.34 / 7.1.22 / 10.0.48.9418+
Joined: Mar 27, 2006
Location: Cleveland, OH USA