IntelliSense incorrectly narrows anyOf branches when one variant requires additional properties

When authoring against a schema that can branch into a route that requires more properties, or a route that requires no additional properties, VSCode's intellisense has some unexpected behaviour:

Schema:

{
    "anyOf": [
        {
            "type": "object",
            "required": [
                "type",
                "thing"
            ],
            "properties": {
                "type": {
                    "type": "string",
                    "const": "A"
                },
                "thing": {
                    "type": "number"
                }
            }
        },
        {
            "type": "object",
            "required": [
                "type"
            ],
            "properties": {
                "type": {
                    "type": "string",
                    "const": "B"
                }
            }
        }
    ]
}

Expected behaviour:

Should show both "A" and "B" as possibilities.

Actual behaviour:

Yet, when hovering over the yellow squiggle, it shows this, which is also not true:

Reproduce the reported schema in VSCode IntelliSense and compare the suggested values and hover warning with the expected A and B branches. No implementation files or tests are named, so trace the JSON language service's anyOf narrowing behavior first; done means both values are offered without an incorrect warning.