(Photo) Copyist’s error?
Students of the classics and ancient documents are used to checking for copyist errors, but a photocopier?
And, of course, you can’t trust the machine to check the copy against the original, since it will probably make the same mistake every time.
Actually, with absolutely everything in the world going digital, this type of problem is becoming inevitable, and endemic. Analogue systems have problems, but digital systems are subject to catastrophic collapse.