Later news implied PJ2's answer. I don't like saying it but the response was rather organised and impressive. Traffic was moving again only a few minutes after the landing and Mrs CVJ was at the airport when offspring, whose plane was barely delayed, was picking up his luggage.
Cathay spokesman said "Warning light for flaps function." Passengers were told they'd be off again in a couple of hours but ended up staying in Vancouver overnight. News reported as "access for inspection was more difficult than expected."