Thanks. I'll see if I can't add that bit.
And no, the AI is not right to run away, as I'll just catch them one by one and slaughter them in boring, easy battles instead of big, huge battles!
Lately I haven't been running elites, as I am constantly training troops from villagers up, so that shouldn't be the problem.
I notice that sometimes, rarely, the AI does seem to collectively go after me (a very weak lord starts to run away, but then pursues me along with a stronger allied army), so it seems like the functionality is there, but faulty somehow.