quick freeze and lightning bolt

now this one is easy to replicate so i assume i dont have to throw in screens and whatnot.. during my match with bohze onkelz i ran into the issue that at some point he threw in a quick freeze.. i was lightning bolting any straglers that dared venture outside the battle and this is when i noticed i could cast a 100 lightning bolts without using mana.. and the visuals were of the chart.. now it seems logical to me that visuals to this degree can cause lag.. perhaps its better to make minions under the effect of quick freeze untargetable by spels