I got a "You did it" message after drowning all three of the goat, lettuce, and wolf followed by a level reset, I guess in a way I did end up solving my problem.
Hah, nice catch! It turns out if all three die within 1 second of each other the game was registering that 0 of the key objects are outside the goal area and triggering the win state before the level gets restarted.
