Black Screenshots on Desktop

Godot Version

v4.3.beta1.official [a4f2ea91a]

Question

This code successfully produces screenshots on Android mobile:

	await RenderingServer.frame_post_draw
	var tex = Globals.main_viewport.get_texture().get_image().get_region(region)
	tex.save_png("user://creator/level_"+str(Globals.creator_level_id)+".png")

image

However on Desktop the screenshots save as a black image:

Am I missing something? Or is this just a bug.