It seems to me, too, that it's a mistake by Fundéu. [note: I had written a commentary on fondue's meaning, but as it was already corrected or published. ]
Acronym for Fundación del Español Urgente
fundéu is incorrectly written, and should be written as "Fondue" being its meaning: The correct term is Fondue. Fondue is a Swiss cheese served in a communal pot seasoning ( caquelon or fondue pot ) on a portable stove ( rechaud ) heated with a candle or spirit.