$map()[] out wrong result

on https://try.jsonata.org/
data:
`{
  "a": [
    {
      "link": "https://abc"
    }
  ]
}`
jsonata:
`$map($$.a,function($v){[""&$v.link,1]})[]`
output:
`[
  [
    "https://abc",
    1
  ]
]`

but on JSONata4Java:
wrong output:
`[ [ "[\"https://abc\"]", 1 ] ]`
($v auto convert to list)

I use $map()[] to avoid $map() auto convert list one element to element