Character not moving despite target position updating

Hiya!
I'm trying to give the animals in my game a state in which they wander around a pasture, but despite the state and target_position seemingly updating correctly, the sprite doesn't move around.

Here's a screenshot with the output, showing that the target_position does update:

Here's my code:

var wander_target_range = 2
var in_pasture_wander_target_range = 100

export var horse_move_speed = 70

var velocity = Vector2.ZERO
var state = STANDING

enum {
	STABLED,
	STANDING,
	WANDERING,
	IN_PASTURE,
	FOLLOWING
}

func _ready():
	state = pick_random_state([STANDING, IN_PASTURE])

func _physics_process(delta):
	match state:
		STABLED:
			pass
		
		STANDING:
			velocity = velocity.move_toward(Vector2.ZERO, horse_move_speed)
			if wanderController.get_time_left() == 0:
				update_wander()
		
		WANDERING:
			pass
		
		IN_PASTURE:
			if wanderController.get_time_left() == 0:
				update_wander()
			change_position(wanderController.target_position, delta)
			if global_position.distance_to(wanderController.target_position) <= in_pasture_wander_target_range:
				update_wander()
			print("Target_position = ", wanderController.target_position)
			print("Start_position = ", wanderController.start_position)
	
		FOLLOWING:
			pass

func pick_random_state(state_list):
	print(state)
	state_list.shuffle()
	return state_list.pop_front()

func update_wander():
	state = pick_random_state([STANDING, IN_PASTURE])
	wanderController.start_wander_timer(rand_range(1, 3))

func change_position(point, delta):
	var direction = global_position.direction_to(point)
	velocity = velocity.move_toward(direction, horse_move_speed)
	sprite.flip_h = velocity.x < 0

And here's the code in WanderController:

export var wander_range = 32

onready var start_position = global_position
onready var target_position = global_position

onready var timer = $Timer

func _ready():
	update_target_position()

func update_target_position():
	var target_vector = Vector2(rand_range(-wander_range, wander_range), rand_range(-wander_range, wander_range))
	target_position = start_position + target_vector

func get_time_left():
	return timer.time_left

func start_wander_timer(duration):
	timer.start(duration)

func _on_Timer_timeout():
	update_target_position()

I've set in_pasture_wander_range both high and low and did the same with horse_move_speed, neither seemed to have an impact.