Why are child node references null when a component is nested?

I'm trying to create a control that contains another control that I've created. I'm running into the problem that when I do this the child component is no longer able to access its child components. They all return null.

For example, I have a component called NumericLineEdit

extends HBoxContainer
class_name NumericLineEdit


@export var value:float:
	get:
		return value
	set(v):
		if value == v:
			return
		value = v
		dirty = true

var dirty:bool = true

# Called when the node enters the scene tree for the first time.
func _ready():
	pass # Replace with function body.


# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(delta):
	if dirty:
		$TextEdit.text = str(value)
		
		dirty = false


func _on_text_edit_text_set():
	value = float($TextEdit.text)

If I run this alone, it works fine. But if I try to include it in another component, I get a bunch of errors about $TextEdit being null. I've tried using the % notation and also calling get_node(), but it's always null when I try to run a scene that uses it as a child.