Based on this amount of information, it's very difficult to say. It may be deliberate dishonesty (they didn't perform the work and said they did). It may be confusion, as claimed (the wires got crossed in communication between the tech and the service writer). Or, it may just be plain old "fell through the cracks." Maybe it wasn't written up correctly, maybe the tech was in a hurry and skimmed over it.
I would bet on Murphy before I would assume, based on the OP, that the service department is systematically not doing the operations they're supposed to.
I would bet on Murphy before I would assume, based on the OP, that the service department is systematically not doing the operations they're supposed to.