"At one point at the Everett factory there were about five 787s without engines that were on the flight line and down at Charleston there were three or four without engines on the flight line," he said. "I don't know what kind of delays that were per their delivery contracts but it's very unusual to see airplanes without engines."
About six years ago the Trent was happily flying on ANA 787s. There was a big RR flag hanging in the Everett factory 'deliverd on time' it said. Meanwhile outside on the flightline, in excess of twenty 787s sat there with concrete blocks hanging off their wings. GE were having trouble getting certification.
As has been said, its not unusual.