I have a load of ancestors dying there also--some from Scandinavian Countries. I have two hypotheses:

1) the place was a battleground for a number of years (Accd to Britanica.com: "The dukes of Burgundy acquired Ponthieu, the Somme towns, and Montdidier under the Treaty of Arras in 1435. Reconquered for France by Louis XI in 1477, Picardy was thereafter a frontier area invaded frequently from the Habsburg Netherlands until the French acquisition of Artois and southern Hainaut in 1659."

2) One very tired but dogged researcher put Y, Somme, Picardie, France when the answer should have been "unknown."