For me, I always read one at a time.  From the Discussion home page I click on read all new, then simply follow through in order.  When the anomaly occurs, it happens after I post a message.  Instead of returning me to the message I just repsonded to, I find myself in a reset situation--different number of unread messages--either a different message or no messages on my screen. 

Sometimes I just read from where I'm at, knowing I'll miss some messages that go-thru.  Sometimes I go back to the first message so I can capture everything new that read through--though the reset has happened again the same read-thru!  Earlier this week it took me from morning to nite through several attempts to get to the final sections of messages.   Finally, sometimes I just go back to the Discusssion home page and start again, of course that's my only option when the reset leaves me with no messages in front of me.  When I do this there are unread messages, I just have to go back to get them.

Anything else you need to know, ask.  I should tell you this is annoying but not a deadly nit--since you changed the way the software keeps track of what we've read and not read, we don't miss any messages--it just takes a while to get to them.  It doesn't even keep me from managing threads, occasionally splitting one, etc.  BTW, none of this ever seems to occur out of any management operation I might do--there's no connection I can see.  It seems to happen strictly during reading the board as if I were any other member.