At about turn 200 in my current game of LH, I started to see what I will refer to as random movement on the part of my soverign's stack of units. If I gave that stack a movement order that took up its full movement allotment (3 as it has tireless march cast on the soverign) then there is no problem. However, if I do anything less then after the ordered move is completed the stack takes the rest of its move off in a random direction. This happens evdery turn and can be a real issue if there are roads in the area to facilitate a long "wander".
One more thing: at the time this problem started my soverign's stack of units was no longer in the move rotation. While it still appeared in the UI list on the left side of the screen it would never come up to move unless I clicked on it myself. Indeed if all the other units moved and the soverign's stack had not then the turn button would glow green indicating that everyone had moved!
I tried taking tireless march off of the soverign but that made no difference.
I hope you can find a solution for this bug.