This has been ongoing for several days. And it doesn't happen ALL the time. Just happened this morning on the WFD #201 thread. I last read it about 9:30pm last night (at home on my laptop). You can see the two latest posts at the top on this screen cap. Butt there are at *least* 15 new posts I haven't read.
And yes, I had already reset the little clock to show the thread in Chrono order. That resetting of the clock doesn't seem to be "sticking".