Mcblend can't export cubes with negative size

[Nusiq]

Example model:

{
	"format_version": "1.12.0",
	"minecraft:geometry": [
		{
			"description": {
				"identifier": "geometry.test",
				"texture_width": 200,
				"texture_height": 200,
				"visible_bounds_width": 2,
				"visible_bounds_height": 2.5,
				"visible_bounds_offset": [0, 0.75, 0]
			},
			"bones": [
				{
					"name": "main",
					"pivot": [0, 0, 0],
					"cubes": [
						{
							"origin": [6, 24, 6],
							"size": [-12, -12, -12],
							"uv": [0, 0]
						}
					]
				}
			]
		}
	]
}

This model improts properly but can't be exported the cube with negative values in the size aren't exported properly.

[Nusiq]

It seems that Minecraft isn't able to render this anyway.