Boeing is investigating a new quality problem with its 787 Dreamliner after discovering that hundreds of fasteners have been incorrectly installed on the fuselages of some undelivered jets, two people familiar with the matter said.

The latest in a series of manufacturing snags affecting the U.S. planemaker involves incorrect “torquing” or tightening in a Boeing plant of more than 900 fasteners per plane — split equally between both sides of the jet’s mid-body, they said.

There is no…