misassembled

adjective

mis·​as·​sem·​bled ˌmis-ə-ˈsem-bəld 

: having its parts put together in an incorrect way : assembled wrongly

The problems … included a wing flap disintegrating in flight on the first day of service, smoke from a misassembled power unit … , and problems in a fire extinguisher system.

—George Tibbits

Word History

First Known Use

1935, in the meaning defined above