Tamed mobs take a while to stop following players in spectator mode.

When a player's game mode is changed to spectator, tamed mobs will continue to follow them for a while. The time it takes for them to stop seems to depend on the player's movement. If the player is standing still, all pets will stop following them within around 10 seconds, but if the player keeps moving, pets can continue to follow them indefinitely.

Relates to MC-46771.