I found a lead. By examining the file data.1pif I noticed that the entries that do not have a url did not have a label field next to the ex url field:
with a bug:
"URLs": [
{
"url": "https:\/\/www.airbnb.fr"
}
]
bug-free:
"URLs": [
{
"label": "site Internet",
"url": "https:\/\/www.box.com\/login\/"
}
]