unclear how to make function argument check produce the same errors as variable assignment

[helios1138]

in the following code

type A = {
  a?: number
  b?: number
}

type B = {
  a?: number
  knownField?: number
}

type C = {
  a?: A,
  knownField?: number | [A, B] | A
}

const c: C = {
  a: {
    a: 1,
    b: 1,
  },
  knownField: [{ a: 1 }, {
    knownField: 1,
    unknownField: 1,
  }],
}

const fn = (c: C) => {}

fn({
  a: {
    a: 1,
    b: 1,
  },
  knownField: [{ a: 1 }, {
    knownField: 1,
    unknownField: 1,
  }],
})

• in the case of variable assignment it correctly highlights the unknownField and produces a nice error that says Object literal may only specify known properties, and 'unknownField' does not exist in type 'B'.
• but in the case of the same value passed as a function argument (of the same type) it highlights the top-level field and a different, less readable error Type '({ a: number; } | { b: number; unknownField: number; })[]' is missing the following properties from type '[A, B]': 0, 1

am I missing something? is there a way to make sure I get the same error and highlighting in both cases?

in typescript playground: