It's been since the begging of alpha and units still will just run by structures without attacking. I havn't seen any recent threads on this. Why is this such a big problem to fix?
Sound like you might be begging for them to fix this bug...? Anyway, yes I also see this bug somewhat frequently and always when my units break through and into the enemy base Have you created a bug report? I will vote it up if you have.
Earlier this morning, I was playing VS the AI, and I got the "opposite bug". When I ordered my units to attack the commander, they just stood there, doing nothing (or firing at nothing...). But as soon as I ordered them to move, they started to attack the commander, and killed it..