The two-time Olympian was pipped to fourth place - with the top three qualifying - by a board length in her semi-final.
She then finished fourth in the B final to finish 10th overall, as Canada's Dominique Maltais claimed the win ahead of France's Nelly Moenne Loccoz and Olympic champion Maelle Ricker. France's Pierre Vaultier won the men's event.
The result means Gillings finishes the World Cup campaign ranked 12th - although her fifth place finish earlier in the season in Austria will boost confidence ahead of next year's Sochi Olympics.
