briefly released millions of tracks that were scraped from Spotify via BitTorrent.
That's just an awkward sentence construction but it makes sense: they released track via Bittorrent. The tracks were scraped from Spotify.
I sold my car that was purchased from a dealership via private party sale.
I charged my laptop that normally accepts 100W via a 20W phone charger.
I would've used a "which" phrase with commas to avoid the confusion, but the sentence as written is valid and makes sense.