InstantSearch.js v1.11.15 | Index vehicles not present in `indices`

I am trying to build a sortBySelector with three replicas however it throws me this exception, even though the index actually exist.

Code:

var search = instantsearch({
    appId:     "APP_ID",
    apiKey:    "API_KEY",
    indexName: "vehicles_desc(online_since)",
    urlSync:   true
});

search.addWidget(
    instantsearch.widgets.sortBySelector({
        container: '#sort-by-selector',
        indices: [
            {name: 'vehicles_desc(online_since)', label: 'Più recenti'},
            {name: 'vehicles_desc(price)',        label: 'Prezzo decrescente'},
            {name: 'vehicles_asc(price)',         label: 'Prezzo ascendente'}
        ],
        label: 'ordina per'
    })
);

Indexes list:
https://gyazo.com/b6ed27355d4810c81520b0abcf01a8c8

Exception:

sort-by-selector.js:65 Uncaught Error: [sortBySelector]: Index vehicles not present in `indices`
    at Object.init (sort-by-selector.js:65)
    at InstantSearch.js:193
    at n (_arrayEach.js:15)
    at r (forEach.js:37)
    at t.value (InstantSearch.js:191)
    at t.value (InstantSearch.js:154)
    at ?q=&hPP=20&idx=vehicles&p=0&is_v=1:181

For some reason, it magically started working. I have not changed anything, just closed and opened again the page.

:face_with_raised_eyebrow:

You can lock this!

Any clue of what happened there? Just being curious :wink:

To be totally honest, I have no clue!