Vel'Koz body invisible in spectator with new Arclight Vel’Koz

Occasionally when I was spectating my friends game Arclight Vel’Koz body would disappear. After re-watching the game I couldn't find what causes this since it doesn't seem to be easily reproducible. It happened 4 times on both play thoughts of the replay although not at the same times as before. Note this was all in the official spectator mode and not a third party replay software.