Another production delay apparently has hit Boeing’s troubled 787 program, and at least one customer, United Continental Holdings, is paring back its delivery schedule for 2012 to account for the issue.

Last month, United Continental detailed a plan that added six Boeing 787-8s and 19 737-900ERs to its fleet in 2012, but on Wednesday the plan had shrunk to 19 737s and just five 787s. United Continental is not offering any explanation for the revision, and a Boeing spokesperson could not reached for comment. However a source with knowledge of the situation tells Aviation Week the slip is attributed to a production issue, and that it is unclear if the delayed aircraft will be added to United Continental’s 2013 fleet schedule.

The United Continental revision coincides with comments from Air New Zealand CEO Rob Fyfe that another delay in his carrier’s 787 delivery scheduled would not be a surprise. In July, an Air New Zealand executive said a delay announced that month would defer delivery of the airline’s first 787-9 to 2014, some four year later than planned when the carrier placed its order. On Wednesday, Reuters quoted Fyfe as saying, “We would not be surprised to see further delays, but we have not yet been advised formally if there are any further delays.”

United Continental is promoting the addition of the “game changing” 787 addition to its fleet and its status as the widebody’s first North American operator. As details about the delay were emerging, the airline was issuing a news release about the final assembly completion of its first 787, and how the “expanded range capabilities, greater fuel efficiency and superior operating economics…will allow United to target new long-haul markets and replace older, less efficient widebody aircraft.”