[<JsonFSharpConverter(BaseUnionEncoding = _)>] not being honored

[<JsonFSharpConverter(BaseUnionEncoding = JsonUnionEncoding.Untagged)>]
type Sql =
  | Sql of sql: string
  | SqlId of sqlId: int
  
let options =
  JsonFSharpOptions.Default()
    .WithAllowOverride(true)
    .ToJsonSerializerOptions()

JsonSerializer.Serialize(Sql "select *", options)

type Sql =
  | Sql of sql: string
  | SqlId of sqlId: int
val options: JsonSerializerOptions
val it: string = "{"Case":"Sql","Fields":["select *"]}"