Godot 3.2 - Area2D collides with TileMap cells

Area2D.gd

extends Area2D

func _ready():
	connect("area_shape_entered", self, "area_shape_entered")

func area_shape_entered(area_id: int, area: Area2D, area_shape: int, self_shape: int):
	var trans = Physics2DServer.area_get_shape_transform(area.get_rid(), area_shape)
	var tilemap = area.get_node("Items") as TileMap
	var offset = 2 * tilemap.cell_size if tilemap.centered_textures else Vector2.ZERO
	var orig = trans.xform(offset)
	var pos = tilemap.world_to_map(orig)
	if tilemap.get_cellv(pos) > -1:
		tilemap.set_cellv(pos, -1)