Kha'Zix W-Void spike didn't hit the scuttle crab

I was playing some khazix and needed to heal. When i used my void spike on the scuttle crab near the dragon it went right through not dealing any damage and therefore not healing me. I didn't have this problem later in the game (all my void spikes did hit the crab) Little information:

• I was under level 6
• crab was affected by red buff
• crab may have been dashing (not sure)

Hope i gave enough information