In my case in the script fragment attached to that line of dialog, at the end of the line the stage is supposed to advance, there's a 24 hour wait and then the stage advances so that the next conversation will fire.
What happens is that the first stage advance never seems to trigger until the player leaves the cell. The conversation winds up repeating until the player goes into a building or the next cell.
I don't know if these two things are tied together.
Anyway, is this just me or is anyone else seeing this? Oblivion never behaved this way and I'm rather stumped as to how to fix it.