The ambient_occlusion field in minecraft:material_instances block component does not affect ambient occlusion.

The ambient_occlusion field in minecraft:material_instances block component does not affect ambient occlusion, even if it is set to false.

The attached sample pack sets the ambient_occlusion to false for the custom block.

The expected result should have no ambient occlusion on the custom block.

Here's the JSON file for the custom block:

{
	"format_version": "1.21.100",
	"minecraft:block": {
		"description": {
			"identifier": "test_block:custom_block",
			"menu_category": {
				"category": "construction"
			}
		},
		"components": {
			"minecraft:geometry": "minecraft:geometry.full_block",
			"minecraft:material_instances": {
				"*": {
					"texture": "test_block_custom_block",
					"render_method": "opaque",
					"ambient_occlusion": false,
					"face_dimming": false
				}
			}
		}
	}
}