I didn't make any structure changes (e.g., ranking or parent-child relationships), I was primarily changing remaining time and corrected estimates.  For example, I was probably increasing the corrected estimates and increasing remaining time.

Thanks for the tip but it doesn't look like my scenario other than, perhaps, the generic case of my "corrected estimates" somehow not placing nicely with my "remaining time".  I'm pretty sure the corrected estimate and remaining times were consistent, i.e., had the appropriate integrity but that WI link makes me wonder if maybe I had corrected the time to say, "4h", with "6h" remaining.. .?  I don't think I did that, but will try that scenario later today and see what happens.