Question about framing

Dear folks,

I am struggling with framing. The result is the same with both pyld and the
playground.

Given a multi-language JSON-LD I want to pick two skos:prefLabels, like that

{
"label_it": {"@language": "it", "@value": {}},
"label_fr": {"@language": "fr", "@value": {}},
"@context": {
"label_it": {"@id": "skos:prefLabel","@language": "it" },
"label_fr": {"@id": "skos:prefLabel","@language": "fr" },
}
}

Full gist here
- https://gist.github.com/ioggstream/e9c4748208728c5abca34a7c6e309284

but the framing mechanism only shows the last field (e.g. label_fr), eg.

{ label_fr: France }  # No Italy here!

Instead, if I don't filter, like below, the framing mechanism dumps all
unmentioned languages in
"skos:prefLabel" field, even if "skos:prefLabel" is not mentioned between
the "@explicit" fields.

{
"label_it": {},
"label_fr": {},
"@context": {
"label_it": {"@id": "skos:prefLabel","@language": "it" },
"label_fr": {"@id": "skos:prefLabel","@language": "fr" },
}
}
Is there a standard way to tell "framing" to strip off specific/unwanted
fields like "skos:prefLabel"?

Thanks ++,
R.