If LX is considered a Community carrier under Regulation 261/400 then one would have to claim in Hungary where the ECJ Jurisprudence would apply. I’m not sure though whether LX is a Community Carrier, would have to check further.
I think with the adoption of EU 261 by Switzerland that became the case.
Furthermore wasn't there success reported by several people here that continued to go that way directly with Swiss but pointing out the jurisdiction they would proceed in as not being Switzerland but another EU country that was just touched by the flight?