According to a report by Notícias ao Minuto, the aircraft, which had 141 passengers on board, was forced to make an emergency landing due to a "technical problem".
"easyJet can confirm that flight EJU4592 from Lisbon to Paris Charles De Gaulle on 15 February was diverted to Bilbao due to a technical problem. The captain carried out a routine landing and the plane was received by emergency services as a routine and precautionary measure".
"Once the plane was in position, all passengers disembarked normally and a replacement plane was arranged so they could continue their flight to Paris. The safety of passengers and crew is the highest priority for easyJet, which operates its fleet of aircraft in strict accordance with all manufacturers' guidelines".