Switching to spectator mode while standing in a nether portal does not make the overlay animation disappear immediately

When you exit a nether portal and switch to spectator mode after you get through, the nether portal overlay animation continues playing for a short amount of time after you are in spectator mode. The animation should disappear instantly.

1. Go through a nether portal.
2. Hit F3+N. You will see the animation for a split second even after you are in spectator mode.