Starting with block definition format versions 1.26.20+, the minecraft:geometry component’s bone_visibility map values were changed to accept numbers instead of booleans. Numeric values make no sense in this context and have no functionality.

Demonstration

The attached content log screenshot demonstrates the issue. The following block definition does not load:

{
	"format_version": "1.26.30",
	"minecraft:block": {
		"description": {
			"identifier": "bug_parsing:custom_block_with_boolean_visibility",
			
			"states": {"bug_parsing:state": [false, true]}
		},
		
		"components": {
			"minecraft:geometry": {
				"identifier": "geometry.bug_parsing.catercorner_cubes",
				"bone_visibility": {
					"bottom_northeast": false,
					"top_southwest": true
				}
			},
			"minecraft:material_instances": {
				"*": {"texture": "blue_glazed_terracotta"}
			}
		},
		"permutations": [
			{
				"condition": "q.block_state('bug_parsing:state')",
				"components": {
					"minecraft:material_instances": {
						"*": {"texture": "red_glazed_terracotta"}
					}
				}
			}
		]
	}
}

This definition works fine in format versions 1.26.10-.

Reproduction

This issue affects any custom block with a geometry component whose bone visibility values use booleans.

This demo code is taken from the behavior pack in the attached world for convenience. This world can be opened (in Minecraft Preview) for inspection or unzipped to access the code associated with such.