Why Tile-marker somtime no erase?

Godot 4.2

Why Tile-marker sometime no erase ? But in zone GridSize - no problem
IMG

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extends TileMap
 
var GridSize = 5
var n_TS = 1
var Dic = {}
var go = 0
		
func _input(event):
	if event is InputEventMouseMotion:
		print("mouse motion")
		go = 1

func _physics_process(delta):
	var tile = local_to_map(get_global_mouse_position())
	
	
	for x in GridSize:
		for y in GridSize:
			erase_cell(0,Vector2i(x,y))
	var all_cell = get_used_cells(0)#get all in tile map lvl 0
	var size = all_cell.size() # total cell in tile map
	var new_set = get_used_rect() # start location x _ y
	#if Dic.has(str(tile)):      
	set_cell(0, tile, n_TS, Vector2i(0,0), 0)
	if go ==1: 
		set_cell(0, tile, 3, Vector2i(0,0), 0)
		go = 0
	

	#erase_cell(0,Vector2i(get_global_mouse_position()))
	print (new_set)
	print (size)
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