Well, this one has been quite a ride.... I've spent weeks trying to figure this out. I was in the middle of trying to craft a more detailed question that might generate some interest. One encoder was working wonderfully the way I expected, and the other, with almost the exact same code was causing all kinds of problems. I was in the process of using my Logic pod (which I love BTW: www.Saleae.com) to see if I could describe the problem better. I had a heartbeat pulse in the main and noticed that it would cut out for almost 3 mS when RB.4 changed. After looking at the datasheet for the ump-teenth time, I realized that I hadn't disabled the Low Voltage Programming option. That was it. Bet I won't take this long to look at that again!
Thanks for all of you who looked at it, and especially those that took the time to give some feedback.
Bo