Strange... try creating summons based in other spells, I see you're making hero spells, may be 4 right?(3 basics + ult) base them on Summon Bear, Summon Quilboar, Summon Hawk and Summon Water Elemental. for diferent kinds of summon like choosing an area for the summon you can use Infernal or Dark Portal, triggers may work too, once I made an Shockwave based ability and where I pointed it the creep was summoned