Lightning orb bug

I know this is VERY old, and I know there are probably hundreds of other threads about it but search didn't find anything

The problem is a few patches ago orb of lightning stopped working properly, I made a custom orb of lighting with 100% chance of purging, and if i give the unit an order to attack a target, it will purge every hit, however, if i attack-move, it will NEVER purge, only when it has an order. It used to work fine but a few patches ago it stopped

Are there any fixes for this? I know there is "A unit is attacked, order attacking unit to attack attacked unit" but that screws up attack move, as it makes the unit follow the other unit if it moves back, and it seems to slow down some unit's attack speeds

Any help is appreciated :)

its orbs bug, it cannot be fixed.

would it be easier to have a dummy orb/object and just use triggers to manually cast purge? excuse my lack of trigger knowledge.. ive always hated triggers...