If you *kill* an ark, then another ark will re spawn if enemies have more arks right?
But if you *kill* the arks that just came before it lands on the ground, kill is and it will disappear?
Only the damage done is shown but the ark is gone haha
Thats not a bug , that only happens if u attack really quickly
Well, it is a visual glitch. I guess. ^^;
If you actually don’t kill the ark and quickly attack it it hovers and part of its upper body and head is cut off (according to its size)
Yea i would say so as well
Glitch 
It is just fun to see them poof away like magic