I have noticed this earlier, but only when I started playing with oozing UB, has it become extremely gamebreaking.

When you use any skill/item that is instant, it will stop your current orders.

You are attacking a demigod, turn on the ooze, your demigod chances target and start chasing butterflies. Enemy is running, you use wand of speed to keep up, your demigod will most likely stop and attack a creep. You are running away from demigod, use wand of speed, your demigod stops and starts to attack the chasing demigod. The list is endless. (Well, not endless, but it has as many entries as there are instant abilities and situations where you might use them.)

If you are doing a melee to death, with nobody else around you, this is not such a big problem, (as you will just start autoattacking them anyway), but this type of behaviour never happens. Usually they try to run, there are other units present, or you are moving. This is a huge problem in any chase situations. (And let's face it, no demigod is known to just surrender, they all try to escape.)

Just wanted to bring this to your attention, so it will be moved up in your list of priorities.