Something wrong with my half slab block

The upper part of the block is rendered black when I don't set light opacity to 0. But the original half slab can be opaque.

Following is my model

{
    "parent": "block/block", 
    "textures": {
        "all": "rhodes:blocks/gray130_8"
    }, 
    "elements": [
        {
            "from": [0, 0, 0], 
            "to": [16, 6, 16], 
            "faces": {
                "down": {
                    "uv": [0, 0, 16, 16], 
                    "texture": "#all", 
                    "cullface": "down"
                }, 
                "up": {
                    "uv": [0, 0, 16, 16], 
                    "texture": "#all"
                }, 
                "north": {
                    "uv": [0, 10, 16, 16], 
                    "texture": "#all", 
					"cullface": "north"
                }, 
                "south": {
                    "uv": [0, 10, 16, 16], 
                    "texture": "#all", 
					"cullface": "south"
                }, 
                "west": {
                    "uv": [0, 10, 16, 16], 
                    "texture": "#all", 
					"cullface": "west"

                }, 
                "east": {
                    "uv": [0, 10, 16, 16], 
                    "texture": "#all", 
					"cullface": "east"

                }
            }
        }
    ]
}