Slitherine

I've just played a game that had Teutons vs Mongols and in it it had multiple instances of Teutonic Knights and knights & Sergeants conducting charges then multiple pursuits of various mongol cavalry sometimes as many as 3-4 units with the heavy Teutonic cavalry sometimes moving in excess of 10 squares in a single turn.
This to me seems utterly ridiculous and unrealistic, any horse carrying that much weight of armour would drop dead with a burst heart trying to run that far that fast in such a short time.

I have a possible solution (not sure how feasible it would be to program), that would be to have heavily armoured cavalry restricted to conducting only one pursuit per turn. This would mean that if one such cavalry charged a unit and either routed it or forced it to evade it would pursue but then if during the pursuit it charges another unit and that unit routs or evades the cavalry unit would stop dead at that point and not pursue. This way the heavily armoured cavalry would not likely move any more than 5 or 6 squares in a turn, which to my mind is much more realistic.
If it routs the second unit you could have the unit suffer from 'no cc' the following turn to offset the advantage of not pursuing the routing.

Multiple pursuits are an intentional part of the game design. They are one of ways that the game simulates the sudden collapse of a wing that could occur in historical battles.

As has been stated elsewhere, the game model is not a "time-slice" model but an episodic model, where sometimes the plodding pace of the battle or pauses in the action on the rest of the field, are overtaken by sudden bursts of activity on others.

This doesn't represent troops moving at super-speed, but rather the rest of the army not being in continuous action all of the time.